Officials in both Austria and Bolivia said that Snowden was not on the plane, which was taking Morales home from a summit in Russia, where he had suggested that his government would be willing to consider granting asylum to the American.

A furious Bolivian Foreign Minister David Choquehuanca said France and Portugal would have to explain why they canceled authorization for the plane, claiming that the decision had put the president's life at risk.

"We don't know who invented this lie" that Snowden was traveling with Morales, Choquehuanca said in La Paz. "We want to denounce to the international community this injustice with the plane of President Evo Morales."

In a midnight press conference, Bolivian Vice President Alvaro Garcia said that not only France and Portugal, but also Italy and Spain were denying the plane permission to fly through their airspace.

He described Morales as being "kidnapped by imperialism" in Europe.

"The ambassador for Spain in Austria has just informed us that there is no authorization to fly over Spanish territory and that at 9 a.m. Wednesday they would be in contact with us again," said Defense Minister Ruben Saavedra, adding that the Spanish government had put as a condition for passage the "revision of the presidential plane."

Earlier, Choquehuanca said that Spain's government allowed Morales' plane to refuel in its territory before flying on to Vienna.

French government officials reached overnight said they could not confirm whether Morales' plane was denied permission to fly over France. Officials at Portugal's Foreign Ministry and National Civil Aviation Authority could not be reached to comment.

Austrian Foreign Ministry spokesman Alexander Schallenberg told The Associated Press that Snowden was not with Morales.

Leaks by Snowden, a former NSA systems analyst, have revealed the NSA's sweeping data collection of U.S. phone records and some Internet traffic, though U.S. intelligence officials have said the programs are aimed at targeting foreigners and terrorist suspects mostly overseas.

He is believed to be in a Moscow airport transit area, seeking asylum from one of more than a dozen countries.

While Bolivia's foreign minister had earlier said officials did not know who was behind the "lie" that Snowden was on Morales' plane, the country's defense minister later expressed no doubt.

"We want to declare very firmly that it was an American story that Edward Snowden was on this flight," said Saavedra at the VIP terminal of Vienna's airport. "This is a plot by the U.S. government to destroy president Morales' image. We say this simply is a lie. And we will confirm this."

Morales himself was present during the improvised press conference but chose not to speak to reporters. Morales will remain at the airport until his plane has been cleared for takeoff.

In Washington, the State Department would not comment directly when asked to speak to the matter and referred the AP to statements on Snowden made at the department's daily briefing. Earlier Tuesday, department spokesman Patrick Ventrell would not discuss how the Obama administration might respond if Snowden left the Moscow airport. "We're not there yet," he said.

Snowden has applied for asylum in Venezuela, Bolivia and 18 other countries, according to WikiLeaks, a secret spilling website that has been advising him. Many European countries on the list including Austria, Finland, Ireland, the Netherlands, Norway, Spain and Switzerland said he would have to make his request on their soil.

One of Snowden's best chances of finding refuge outside the United States may hinge on Venezuelan President Nicolas Maduro, who was also in Russia on Tuesday.

Maduro told Russian reporters that his country has not received an application for asylum from Snowden and dodged the question of whether he would take him with him when he left.

But Maduro also defended the former National Security Agency systems analyst.

"Who must protect Snowden? This is the question. This young man of 29 was brave enough to say that we need to protect the world from the American imperial elite, so who should protect him?" Maduro said in response to a question from journalists covering a ceremony to rename a Moscow street after Chavez. "All of mankind, people all over the world must protect him."

Maduro was scheduled to spend Wednesday in neighboring Belarus before returning to Venezuela.

In Venezuela, Foreign Minister Elias Jaua said that changing the flight's route without checking on how much fuel it had endangered Morales' life.

"All the countries that have denied permission for the flight of our brother president, Evo Morales, must be held responsible for his life and his dignity as president."

Another possible landing spot for Snowden is Ecuador, where Wikileaks founder and publisher Julian Assange has been seeking asylum.

"We are willing to analyze Mr. Snowden's request for asylum and this position has not changed," said Ecuadorean Foreign Minister Ricardo Patino on Tuesday. "What we have said is that we will be able to analyze the request when Mr. Snowden is in Ecuadorean territory or in an Ecuadorean mission."

Patino added that two weeks ago a hidden microphone was found in Ecuador's embassy in London, where Assange is holed up. "We want to find out with precision what the origin of the apparatus is."

Snowden, who recently turned 30, withdrew a bid for asylum in Russia when he learned the terms Moscow had set out, according to Putin's spokesman Dmitry Peskov. Putin said on Monday that Russia was ready to shelter Snowden as long as he stopped leaking U.S. secrets.

At the same time, Putin said he had no plans to turn over Snowden to the United States.

Rebuffed by Russia's president, the Obama administration has recently toned down demands Snowden be expelled from the Moscow airport in a sign that the U.S. believes he is not worth scuttling diplomatic relations between the former Cold War enemies.

On Monday, WikiLeaks posted a statement attributed to Snowden on its website, in which he slams Obama for "using citizenship as a weapon."

"Although I am convicted of nothing, (the United States) has unilaterally revoked my passport, leaving me a stateless person," Snowden says in the statement. "Without any judicial order, the administration now seeks to stop me exercising a basic right. A right that belongs to everybody. The right to seek asylum.

"Their purpose is to frighten, not me, but those who would come after me."

____

Associated Press writer George Jahn contributed to this report from Vienna, Austria, and Carlos Valdez from La Paz, Bolivia.

NASHVILLE, Tennessee (Reuters) - Jan Simek, leader of the team that discovered the oldest known cave art in the United States, says he is far from finished.

The 60-year-old science professor at the University of Tennessee still plans to belly crawl through caves or climb atop bluffs in the hope of finding more art in his cave-rich state.

The Simek team's discovery of 6,000-year-old art in the Cumberland Plateau, a division of the Appalachian Mountains extending from southern West Virginia to northern Alabama, is featured in this month's issue of Antiquity, the archeological journal published by Britain's Durham University.

"Yes, we have cave art that is 6,000 years old," Simek said. "But we don't want to say it is the oldest rock art (in the United States)."

Simek told Reuters there might be ancient rock art in 400 or 500 of the 9,000 caves recorded in the limestone and sandstone bedrock of Tennessee.

His team has explored about 1,000 of them so far. "We are in the early stages of this, to be honest," he said.

Cave locations are kept secret because of concerns that looters could damage any archeological treasures that may be inside.

By global standards, 6,000-year-old cave art is still relatively youthful. Experts say the famous Paleolithic paintings in Lascaux, France, are as old as 20,000 years; other drawings found in Australia and southern Africa are believed to be older still.

Nonetheless, archaeologists and Native Americans are excited about the discoveries by Simek and his team: Alan Cressler of the U.S. Geological Survey; Nicholas P. Hermann of Mississippi State University and Sarah C. Sherwood of the University of the South in Sewanee, Tennessee.

Albert Bender, a Cherokee and board adviser for the Nashville-based Native American Indian Association of Tennessee, said the discovery "shows the sophistication of Native American society in the South going back thousands and thousands of years."

Michael Moore, director and state archeologist in Tennessee's Division of Archaeology, described the team's find as "extremely exciting and extremely significant" for "the different insights into prehistoric culture."

RELIGIOUS CONNECTION

Simek said his team's main focus was on the connection of the art to religion. Some of the drawings show humans hunting or engaging in magical activities like flying; others depict more mythological or spiritual images such as serpents and circles.

"We know ... that these folks had recognized multiple layers of reality, and humans only occupied one of the layers in the middle," he said. "But they interacted with and were influenced by a celestial world, an upper world that had certain creatures and spirits associated with it and an underworld that had other spirits associated with it."

Simek said this multi-tiered religious view was represented by the figures on bluffs, those in the open air, and those beneath the ground in the Cumberland Plateau.

He compares the spiritual view of the artists with other religions, including Christianity.

"Christ was taken to the top of the mountain, crucified, taken down, put in a cave and from there was reborn," he said. "Those are the vertical levels of our spiritual world."

To him, the artwork and the sheer physical demands required for the painters and carvers to reach so high on the bluffs as well as so far below ground to depict their spiritual hopes and fears are proof that a sophisticated society predated people who currently call Tennessee home.

"This stuff is thoughtful, insightful, profound, sacred," said Simek, who fortunately is neither claustrophobic nor afraid of the dark. "These people have taught me a great deal about the power of the human mind."

Then he stopped and added: "It's a lot of fun."

(Reporting by Tim Ghianni; Editing by Arlene Getz and Lisa Von Ahn)

The conversation is no longer solely about how to save the planet by cutting carbon emissions. It's becoming more about how to save ourselves from the warming planet's wild weather.

It was Mayor Michael Bloomberg's announcement last week of an ambitious plan to stave off New York City's rising seas with flood gates, levees and more that brought this transition into full focus.

After years of losing the fight against rising global emissions of heat-trapping gases, governments around the world are emphasizing what a U.N. Foundation scientific report calls "managing the unavoidable."

It's called adaptation and it's about as sexy but as necessary as insurance, experts say.

It's also a message that once was taboo among climate activists such as former Vice President Al Gore.

In his 1992 book "Earth in the Balance," Gore compared talk of adapting to climate change to laziness that would distract from necessary efforts.

But in his 2013 book "The Future," Gore writes bluntly: "I was wrong." He talks about how coping with rising seas and temperatures is just as important as trying to prevent global warming by cutting emissions.

Like Gore, governmental officials across the globe aren't saying everyone should just give up on efforts to reduce pollution. They're saying that as they work on curbing carbon, they also have to deal with a reality that's already here.

In March, President Barack Obama's science advisers sent him a list of recommendations on climate change. No. 1 on the list: "Focus on national preparedness for climate change."

"Whether you believe climate change is real or not is beside the point," New York's Bloomberg said in announcing his $20 billion adaptation plans. "The bottom line is: We can't run the risk."

On Monday, more than three dozen other municipal officials from across the country will go public with a nationwide effort to make their cities more resilient to natural disasters and the effects of man-made global warming.

"It's an insurance policy, which is investing in the future," Mayor Kevin Johnson of Sacramento, Calif., who is chairing the mayors' efforts, said in an interview Friday. "This is public safety. It's the long-term hazards that could impact a community."

Discussions about global warming are happening more often in mayors' offices than in Congress. The Obama administration and local governments are coming up with thousands of eye-glazing pages of climate change adaptation plans and talking about zoning, elevation, water system infrastructure, and most of all, risk.

"They can sit up there and not make any policies or changes, but we know we have to," Broward County, Fla., Mayor Kristin Jacobs said. "We know that we're going to be that first line of defense."

University of Michigan professor Rosina Bierbaum is a presidential science adviser who headed the adaptation section of the administration's new National Climate Assessment. "It's quite striking how much is going on at the municipal level," Bierbaum said. "Communities have to operate in real time. Everybody is struggling with a climate that is no longer the climate of the past."

Still, Bierbaum said, "Many of the other developed countries have gone way ahead of us in preparing for climate change. In many ways, the U.S. may be playing catch-up."

Hurricanes, smaller storms and floods have been a harsh teacher for South Florida, said Jacobs.

"Each time you get walloped, you stop and scratch your head ... and learn from it and make change," she said. "It helps if you've been walloped once or twice. I think it's easier to take action when everybody sees" the effect of climate change and are willing to talk about being prepared.

What Bloomberg announced for New York is reasonable for a wealthy city with lots of people and lots of expensive property and infrastructure to protect, said S. Jeffress Williams, a University of Hawaii geophysicist who used to be the expert on sea level rise for the U.S. Geological Survey. But for other coasts in the United States and especially elsewhere in the poorer world, he said, "it's not so easy to adapt."

Rich nations have pledged, but not yet provided, $100 billion a year to help poor nations adapt to global warming and cut their emissions. But the $20 billion cost for New York City's efforts shows the money won't go far in helping poorer cities adapt, said Brandon Wu of the nonprofit ActionAid.

At U.N. climate talks in Germany this past week, Ronald Jumeau, a delegate from the Seychelles, said developing countries have noted the more than $50 billion in relief that U.S. states in the Northeast got for Superstorm Sandy.

That's a large amount "for one storm in three states. At the same time, the Philippines was hit by its 15th storm in the same year," Jumeau said. "It puts things in context."

For poorer cities in the U.S., what makes sense is to buy out property owners, relocate homes and businesses and convert vulnerable sea shores to parks so that when storms hit "it's not a big deal," Williams said. "I think we'll see more and more communities make that decision largely because of the cost involved in trying to adapt to what's coming."

Jacobs, the mayor from South Florida, says that either people will move "or they will rehab their homes so that they can have a higher elevation. Already, in the Keys, you see houses that are up on stilts. So is that where we're going? At some point, we're going to have to start looking at real changes."

It's not just rising seas.

Sacramento has to deal with devastating droughts as well as the threat of flooding. It has a levee system so delicate that only New Orleans has it worse, said Johnson, the California capital's mayor.

The temperature in Sacramento was 110 this past week. After previous heat waves, cities such as Chicago, Philadelphia and Washington, D.C., have come up with cooling centers and green roofs that reduce the urban heat island affect.

Jacobs said cities from Miami to Virginia Beach, Va., are coping with mundane efforts: changes in zoning and building codes, raising the elevation of roads and runways, moving and hardening infrastructure. None of it grabs headlines, but "the sexiness is ... in the results," she said.

For decades, scientists referenced average temperatures when they talked about global warming. Only recently have they focused intensely on extreme and costly weather, encouraged by the insurance industry which has suffered high losses, Bierbaum said.

In 2012, weather disasters not necessarily all tied to climate change caused $110 billion in damage to the United States, which was the second highest total since 1980, the National Oceanic and Atmospheric Administration said last week.

Now officials are merging efforts by emergency managers to prepare for natural disasters with those of officials focused on climate change. That greatly lessens the political debate about human-caused global warming, said University of Colorado science and disaster policy professor Roger Pielke Jr.

It also makes the issue more local than national or international.

"If you keep the discussion focused on impacts ... I think it's pretty easy to get people from all political persuasions," said Pielke, who often has clashed with environmentalists over global warming. "It's insurance. The good news is that we know insurance is going to pay off again."

Describing these measures as resiliency and changing the way people talk about it make it more palatable than calling it climate change, said Hadi Dowlatabadi, a University of British Columbia climate scientist.

"It's called a no-regrets strategy," Dowlatabadi said. "It's all branding."

All that, experts say, is essentially taking some of the heat out of the global warming debate.

___

Associated Press writers Karl A. Ritter in Bonn, Germany, Jennifer Peltz in New York and Tony Winton in Miami contributed to this report.

___

Online:

Federal government's National Climate Assessment chapter on adaptation: http://1.usa.gov/154qUGs

The national mayors' efforts to promote adaptation: http://www.resilientamerica.org

Georgetown University's Climate Center primer on adaptation: http://www.georgetownclimate.org/adaptation

___

Seth Borenstein can be followed at http://twitter.com/borenbears

First of a two-part package on adapting to climate change. Tomorrow: Snapshots of what cities are doing around the world.

Karlyn Tilley, a spokeswoman for the Golden Fire Department, tells The Denver Post (http://bit.ly/10EYRgW ) the man was climbing with his two adult children while using technical gear at a popular cliff about 20 miles west of Denver. She says he fell at about 1 p.m. Saturday.

About a dozen climbers who were nearby helped with the rescue and brought the man off the mountain within an hour of the fall.

Tilley says the man was unresponsive and not breathing when paramedics arrived.

___

Information from: The Denver Post, http://www.denverpost.com

Fourteen states east of the Rockies had spring temperatures that ranked among their 10 lowest since record-keeping started more than 100 years ago. In Alaska, residents of Galena were evacuated in May aftertemperatures slowed the annual melting of Yukon River ice, causing an ice jam that flooded the town.

The low temperatures also meant fewer tornadoes than average struck in May. However, two devastatingThe powerful twisters, one of which was the widest ever recorded, killed more than 20 people and destroyed thousands of homes and businesses. "We saw some very high impact tornado situations, but it's been a very slow spring compared to the last decade," said Deke Arndt, chief of the climate monitoring branch at the NCDC.

Jet stream shifts

Shifts in the jet stream, partly seasonal and partly caused by high-latitude weather systems, were responsible for the unusual spring chill, according to the NCDC. Thebrought cold Arctic air to the Midwest and East.

The chilly season followed a string of warmer-than-normal springs, part of the natural variation expected as the climate warms, Arndt said. "We won't stop having colder-than-normal episodes even as the world continues to warm," Arndt told LiveScience.

Even though , overall, the year-to-date average national temperature of 43.6 degrees Fahrenheit (6.4 degrees Celsius) was 0.2 F (0.3 C) above the 20th-century average, the NCDC report said.

Plains drought improves, West still parched

Snow and rain soaked the Plains this spring, taking the edge off a lingering . Iowa had its wettest spring on record, with 8.84 inches (22.45 centimeters) of precipitation, according to the NCDC report. Above-average precipitation in May also contributed to flooding along several major rivers in the Midwest, including the Mississippi River and the Illinois River, the NCDC said.

But the cold and wet spring stopped west of the Rockies. Drought continues to parch the West, where it was warm and dry from January through May. California saw only 29 percent of its average precipitation for January through May, the report said. Areas of extreme drought increased in southeastern Colorado and New Mexico. []

"This is still a big drought event, and it's likely going to be one of the major weather and climate stories of 2013," Arndt said. "It's going to continue to present major problems this year."

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Now the museum is slowly coming back to life, helped by millions of dollars in U.S. and other foreign aid. Every day 300 to 400 visitors a day come to see the collections of sculptures, jewelry, coins and other artifacts dating from the Stone Age through the 20th century.

A new exhibit, "The 1,000 cities of Bactria," focuses on a northern region of Afghanistan that accumulated great wealth, thanks to its location along the Silk Road and several other important trade routes from China and India.

But the exhibit won't include any of the legendary "Bactrian gold," a collection of tens of thousands of gold and silver coins, crowns and jewelry more than 2,000 years old because the museum lacks the security measures to keep it safe. Instead the collection travels the world, already displayed at the British Museum in London, the National Gallery of Art in Washington and other institutions. It is now at the Melbourne Museum in Australia.

"There were a lot of problems, but year by year we're trying to solve these," director Omra Khan Masoudi said on a tour of the museum on Friday. "Now it's starting to look like a museum."

The two-floor museum is across the street from Kabul's famous Darul Aman Palace, which still lies in ruins from fierce fighting in the area in the early 1990s during the civil war. The museum was also badly damaged in the fighting, and in the chaos some 70 percent of its collection about 70,000 pieces was lost to looting.

With the help of foreign governments, some 9,000 of those artifacts have been recovered so far from the U.S., Britain, Germany and elsewhere.

Despite the losses, the collection is still impressive.

At the front door, a second century limestone statue of a Kushan Empire prince greets visitors missing its head from devastation wrought under the Taliban in 2001 when they embarked on a campaign to destroy pre-Islamic art.

Five wooden sculptures from Nuristan dating to the 18th century, each about two meters (five to six feet) tall, loom over the end of the museum's great hall, and a special exhibit on Buddhism in Afghanistan contains some of the first examples of sculptures depicting Buddha.

"I believe the National Museum of Afghanistan can be one of the richest museums in the region, or in the world," Masoudi said.

Some $3 million from the Afghan government and another $5 million from the U.S. Embassy, as well as donations from Italy, Japan and the Netherlands, have helped bring the museum to the state it is in today.

Another $3 million project funded by the U.S. State Department involves experts from the University of Chicago helping to catalog and document all of the museum's inventory, after some 90 percent of object records were lost during the years of turmoil.

But restoration can only go so far. Frequent power cuts, issues with heating and lighting and above all else insufficient security mean the museum needs a new building, Masoudi said.

Plans are already drawn up, and the museum is planning on embarking next year on a capital campaign to raise the $30 million needed for the construction.

That's why the Bactrian gold, which had been hidden and thought lost until resurfacing in 2003, is currently more valuable abroad than at home, because it raises interest in the museum.

"This exhibits shows the other face of Afghanistan," Masoudi said. "It is an ancient civilization with its own unique art it opens a window for us to the other nations."

Mortgage buyer Freddie Mac said Thursday that the rate on the 30-year low stayed at 3.53 percent. That's near the 3.31 percent reached in November, which was the lowest on record going back to 1971.

The rate on the 15-year fixed mortgage stayed at 2.77 percent for a second week. The record low is 2.63 percent.

The one-year adjustable mortgage was the only rate to change this week. It averaged 2.61 percent, up from 2.53 percent last week.

Cheap mortgages are giving a boost to the slowly improving housing market.

Increased sales have helped to push home prices up, which makes consumers feel wealthier and helps to boost consumer spending. In addition, the increased housing demand is boosting new home construction.

Still, housing has a long way to go to achieve a full recovery. And many people are unable to take advantage of the low rates, either because they can't qualify under stricter lending rules or they lack the money to meet larger down payment requirements.

To calculate average mortgage rates, Freddie Mac surveys lenders across the country on Monday through Wednesday of each week. The average doesn't include extra fees, known as points, which most borrowers must pay to get the lowest rates. One point equals 1 percent of the loan amount.

The average fee for 30-year loans was 0.8 point, the same as last week. The fee for 15-year mortgages was 0.8 point, up from 0.7 point last week. The fee for one-year adjustable rate mortgages was 0.3 point, down from 0.4 point last week.

Freddie Mac said that the average rate on five-year adjustable-rate mortgages edged up to 2.64 percent this week from 2.63 percent last week. The fee stayed the same at 0.6 point.

CAPE CANAVERAL, Florida (Reuters) - NASA has selected Space Florida, a state-backed economic development agency, to take over operations, maintenance and development of the space shuttle's idled landing site at the Kennedy Space Center in Florida, officials said on Friday.

Terms of the agreement, which have not yet been finalized, were not disclosed, but Space Florida has made no secret about its desire to take over facilities no longer needed by NASA to develop a multi-user commercial spaceport, somewhat akin to an airport or seaport.

The state already has a lease for one of the space shuttle's processing hangars, and an agreement with Boeing to use the refurbished facility for its planned commercial space taxi.

The so-called CST-100 is one of three spaceships under development in partnership with NASA to fly astronauts to the International Space Station, a permanently staffed, $100 billion research outpost that flies about 250 miles above Earth.

NASA ended its 30-year space shuttle program in 2011, leaving Russia's Soyuz capsules as the sole means to transport crews to the station, a service that costs the United States more than $70 million per person. NASA hopes to buy rides commercially from a U.S. company by 2017.

The shuttle's retirement left the Kennedy Space Center loaded with equipment and facilities that are not needed in NASA's new human space initiative, which includes a heavy-lift rocket and deep-space capsule for journeys to asteroids, the moon and other destinations beyond the space station's orbit.

Last year, NASA solicited proposals for agencies or companies to take over the shuttle landing facility and its 15,000-foot (4,572-meter) runway, one of the longest in the world.

Additional landing site infrastructure includes an aircraft parking ramp measuring 480 by 550 feet, a landing aids control building, a 90-foot (27-meter) wide shuttle tow way, an air traffic control tower and a 23,000-square-foot (2,137-square-meter) enclosure used by convoy vehicles that serviced the shuttles after landing.

In addition to shuttles returning from orbit, the runway is used by heavy transport aircraft, military cargo planes, T-38, Gulfstream G-2 and F-104 aircraft, and helicopters.

Space Florida would like that list to also include suborbital passenger ships, such as the two-seater Lynx space plane being developed by privately owned XCOR Aerospace, orbital vehicles like Microsoft co-founder Paul Allen's air-launched Stratolaunch Systems, and unmanned aircraft.

"We look forward to working with NASA and KSC leadership in the coming months to finalize the details of this transaction in a way that will provide the greatest benefit to incoming commercial aerospace businesses," Space Florida President Frank DiBello said in a statement.

Turning the shuttle landing facility over to a commercial operator will save NASA more than $2 million a year in operations and maintenance costs, documents posted on the agency's procurement website show.

The landing facility also includes a 50,000-square-foot (4,645-square-meter) hangar that Space Florida already owns. A commercial flight services company, Starfighters Aerospace, currently operates there.

NASA said it received five bids for the shuttle landing facility, including the winning one.

The announcement that Space Florida had been chosen was made by NASA administrator Charles Bolden who was in Florida for the opening of the shuttle Atlantis exhibit at the Kennedy Space Center Visitor Complex.

Proposals to take over one of the shuttle's two launch pads are due on July 5.

(Editing by Jane Sutton and Paul Simao)

Seoul said experts were investigating attacks on the websites of the South Korean presidential Blue House and prime minister's office, as well as some media servers. There were no initial reports Tuesday that sensitive military or other key infrastructure had been compromised.

The attacks in South Korea did not appear to be as serious as a March cyberattack that shut down tens of thousands of computers and servers at South Korean broadcasters and banks. Seoul alerted people to take security measures against cyberattacks.

The North Korean websites that shut down Tuesday included those belonging to the national airline, Air Koryo, the Rodong Sinmun newspaper, the North's official Uriminzokkiri site and Naenara, the country's state-run Internet portal. All but Air Koryo were operational a few hours later.

South Korean National Intelligence Service officials said they were investigating what may have caused the shutdown of the North Korean websites. North Korea didn't make any immediate comment.

Operators of several Twitter accounts who purported to be part of a global hackers' collective known as Anonymous claimed that they attacked North Korean websites. The Associated Press received no answer to several requests to speak to the Twitter users. Shin Hong-soon, an official at South Korea's science ministry in charge of online security, said the government was not able to confirm whether these hackers were linked to Tuesday's attack on South Korean websites.

It wasn't immediately clear who was responsible. North and South Korea have traded accusations of cyberattacks in recent years.

South Korean officials blamed Pyongyang for a March 20 cyberattack that struck 48,000 computers and servers, hampering banks and broadcasters for several days, although television programming was not interrupted and officials have said that no bank records or personal data were compromised. Seoul officials said in April that an initial investigation pointed to a North Korean military-run spy agency as the culprit.

North Korea blamed South Korea and the United States for cyberattacks in March that temporarily disabled Internet access and websites in North Korea.

Experts believe North Korea trains large teams of cyber warriors and that the South and its allies should be prepared against possible attacks on key infrastructure and military systems. If the inter-Korean conflict were to move into cyberspace, South Korea's deeply wired society would have more to lose than North Korea's, which largely remains offline.

The shutdowns came on a war anniversary that both countries were marking with commemorations. They also are gearing up for the 60th anniversary of the end of the fighting July 27, a day North Koreans call "Victory Day" even though the Korean War ended in a truce, not a peace treaty.

Tens of thousands of North Koreans were gathering Tuesday to Pyongyang's main Kim Il Sung Square for the largest of many rallies around the nation denouncing the United States. On Monday evening, men lined up in the shadow of the capital's iconic Juche Tower to practice coordinating their steps as they hoisted signs reading "Sweep away the imperialist American aggressors," ''sworn enemies," and "U.S. troops out of South Korea" while a man with a megaphone barked out orders.

In South Korea, thousands of people, including Korean war veterans, gatherrf at Jamsil Stadium in Seoul for a commemoration. Two South Korean army units held military drills in Yeoncheon in Gyeonggi Province, near the demilitarized zone, defense officials said in Seoul.

North Korea in recent weeks has pushed for diplomatic talks with Washington. Tensions ran high on the Korean Peninsula in March and April, with North Korea delivering regular threats over U.N. sanctions and U.S.-South Korean military drills.

The attendees came to the first-ever Space Hacker Workshop on Saturday and Sunday (May 4 and 5) to learn about how they could build and fly experiments on a new generation of manned suborbital vehicles such as XCOR Aerospace's .

The event, which was sponsored by the Silicon Valley Space Center and Citizens in Space, attracted high-school and college students, university professors, space professionals, scientists, technology experts and others interested in this emerging field. []

New reusable vehicles slated to come online soon will provide affordable and repeated access to space for professional and amateur scientists and help to revolutionizeand science education, said Citizens in Space founder Ed Wright.

"With the suborbital vehicles being developed...there's going to be an opportunity to fly many thousands of small payloads on suborbital vehicles every year," Wright said.

Citizen space scientists

Citizens in Space is a program run by Wright's Texas-based organization, the U.S. Rocket Academy, which has purchased 10 flights aboard the two-seat Lynx just for research. Ten lucky citizen scientists will get to fly in the passenger seat of the vehicle and operate the experiments that they have designed and built. Five of those slots already have been filled.

So, just how cheap will it be to fly experiments in space? Wright said that while a typical tinymight cost between $3,000 and $5,000 to build and another $100,000 or more to launch into orbit, developing and flying scientific payloads aboard the Lynx will be many orders of magnitude cheaper.

"At the base level, you're going to have people who are able to build an experiment for $200 or less and have an opportunity to fly in space through programs such as Citizens in Space, and I think this is just going to change everything," Wright said.

"We may reach the point in five or 10 years where every high school science major will have the opportunity to build and fly a payload in space during the course of his academic career before he graduates, he added.

The development of suborbital vehicles such as the Lynx andis coming at a time when maker spaces are popping up all over the country. Wright said these joint work spaces are perfect places for people to build the types of do-it-yourself science experiments that Citizens in Space wants to fly.

Wright's academy is developing the Lynx Cub Payload Carrier, a unit that can hold up to a dozen small experiments in a space behind the pilot's seat. The carrier will give XCOR the ability to flyin the passenger's seat while also carrying scientific experiments as secondary payloads.

A seat on Lynx costs $95,000, while a ticket to fly on SpaceShipTwo which last week made its will set you back $200,000 at the moment. (Virgin Galactic founder Sir Richard Branson said recently that ticket prices would soon temporarily rise to $250,000.) []

A range of experiments

Four XCOR employees traveled 300 miles (500 kilometers) north from the town of Mojave, where they are building the first Lynx, to address the Space Hacker audience and answer questions.

Khaki Rodway, XCOR's director of payload sales and operations, gave an overview of Lynx's capabilities and a progress update on the assembly of the first vehicle, which could fly by the end of this year.

"We're doing it because there's lots of stuff to do," Rodway said of the emerging market for experiments.

During the two-day workshop, participants heard talks about the experiments that will be carried out in the microgravity environment and vacuum of space. These experiments will range across many different fields, including materials processing, fluid dynamics, life sciences, protein crystal growth and technology demonstrations.

NASA astronaut Yvonne Cagle talked about sending odd "water bears" into space. Water bears, also known as tardigrades, are tiny organisms that are virtually impervious to heat, radiation and vacuum conditions. Cagle believes that by studying water bears, scientists can learn a great deal about how to help humans adapt to space.

Jason Reimuller, president of the company Integrated Spaceflight Services, told the audience about his Polar Suborbital Science in the Upper Mesosphere (PoSSUM) campaign, which will use a Lynx to study the dynamics of clouds over the North Pole. The vehicle will operate out of a high-altitude spaceport in either Alaska or Sweden, Reimuller said.

Ryan Gillespie, an aerospace engineer from Sunnyvale, Calif., said he is interested in pursuing Citizens in Space's High Altitude Astrobiology Challenge, which is offering cash prizes of up to $10,000 for the development of a device that will collect micro-organisms living at the edge of space.

I'm not so much interested in the $10,000 it's more the fact that when you come up with anything, it needs a purpose," Gillespie said. "Here's something that actually has a purpose for mankind."

Driving technology forward

Richard Mains of Mains Associates, who works with the NASA Flight Opportunities Program that funds experiments on , said these new spaceships are driving technology development at a much faster rate than traditional NASA programs tend to do.

"I think what's actually going on here with these reusable suborbital launch vehicles is kind of a whole new paradigm where you're not putting a payload up onfor six months," Mains said. "And these vehicles aren't that big. But they are flying very often, So these payloads now have to be small, smart, autonomous very very easy to kind of activate and deactivate, reprogram, get data out of."

"I see all of that driving technology in a very, very interesting fashion," Mains added, mentioning the emergence of open-source platforms as another powerful driver. "So I'm very excited about what I've heard here."

Silicon Valley was a perfect location to hold the workshop given that it's at the leading edge of technology development, Mains said.

Wright said he was extremely pleased with the workshop, which sold all of its 95 tickets and had a waiting list on Saturday morning.

"I think it's gone very well," Wright said. "It's really been a great turnout. It's been very exciting for everyone here. The people from the NASA Flight Opportunities program were very excited about this. XCOR was very excited about this."

Wright says he hopes to conduct five or six additional workshops in cities across the country over the next year.

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