TOKYO (Reuters) - Asian shares began the new month with a cautious tone on Monday as uncertainty over how much longer the current U.S. stimulus would continue prompted investors to book profits from recent highs and pulled global equities lower.

Speculation over whether and when the U.S. Federal Reserve would start scaling back its current massive bond-buying program emerged following a string of positive U.S. data and was the catalyst for corrections across markets which had drawn strong support from the Fed's largesse.

Investors will be cautious ahead of more data this week from the United States as well as from China, both of which would offer clues to growth and demand prospects in the world's largest economies.

"The Federal Reserve's willingness to alter the pace of purchases sooner than markets had previously expected has meant that markets remain attuned to the incoming data flow in the U.S.," Barclays Capital said in a research note.

"This week brings the potential for more market-moving data in the U.S.," it said, referring to the May ISM manufacturing index due later in the session and the more important monthly nonfarm payrolls data due on Friday. The Fed has said it would keep up the stimulus campaign until the employment situation improved.

MSCI's broadest index of Asia-Pacific shares outside Japanremained pressured, after falling to its lowest in nearly seven weeks on Friday and ending May down 4.7 percent for its worst monthly performance in a year.

Australian shareswere down 0.2 percent while South Korean shares opened down 0.4 percent.

Even Japan's Nikkei stock average , which has outperformed the Asian bourses, eased, opening down 1.6 percent and hit a six-week low early on Monday.

"Investors are mostly likely to stay on the sidelines because we have a lot of important data this week from the States," said Takashi Hiroki, chief strategist at Monex Inc.

The Standard & Poor's 500 Indexposted consecutive weekly losses for the first time since November as investors took some money off the table after the index rallied 14.3 percent, the best first five months of the year since 1997, and ended May up for the seventh straight month of gains - its longest streak of monthly gains since 2009.

Reflecting heightening investor nervousness, the CBOE Volatility index , which measures expected volatility in the Standard & Poor's 500 indexover the next 30 days, hit a six-week high on Friday.

Data on Friday showed U.S. Chicago Purchasing Managers Index rose far more than expected in May, released ahead of the national manufacturing data due later this session.

The strong business activity data fanned worries about the Fed slowing its bond purchases later this year and sent U.S. Treasury prices lower on Friday, capping the worst month for the market in nearly 2-1/2 years.

Later in the Asia session, China is set to release the official services PMI and the final HSBC survey that focuses on smaller private sector firms. Over the weekend, China said its official PMI rose to 50.8 in May from 50.6 in April, beating market expectations and raising optimism that the world's second-largest economy may be stabilizing.

"While the data may ease some concerns of rapid deteriorating of the Chinese economy, the impact may be short-lived," ANZ said in a commentary, noting that this single indicator did not change its view on China's softening economic condition.

"Structural reforms are needed in order to help sustain the growth prospect ... inconsistent data will continue to complicate China's economic policy making and potentially impair the judgment of policymakers," ANZ added.

The dollar was steady around 100.40 against the yen, having hit a three-week low of 100.22 on Friday. The dollar index , measured against a basket of six key currencies, was down 0.11 percent after touching a three-week low on Thursday.

U.S. crude futures fell 0.6 percent to $91.43 a barrel.

Amid global equity market corrections spurred by concerns over the Fed's stimulus outlook, EPFR Global said on Friday the equity funds it tracks recorded collective outflows of $2.79 billion during the week ending May 29 as retail redemptions hit a year-to-date high while bond funds attracted $1.37 million, their second lowest total of 2013.

(Additional reporting by Dominic Lau in Tokyo; Editing by Eric Meijer)

Gao was the first city where Islamic extremists were pushed out by French forces in January, and is now where the population is staging the first act of protest against the French.

The youth staged the sit-in in an area in the center of the city that came to be known as "Shariah Square" during the city's 10-month-long occupation last year by the radical Movement for Oneness and Jihad in West Africa, or MUJAO. Countless accused thieves were strapped to chairs and had their hands sawed off by the jihadists in the square, in scenes of horror that had never previously been witnessed in this part of the world that has long practiced a more tolerant version of the religion.

Moussa Boureima Yoro, who took part in the protest, said the youth are unhappy with what they see as France's bias toward the Tuaregs, including the National Movement for the Liberation of the Azawad, or NMLA, a Tuareg rebel group which is currently controlling the city of Kidal, located 350 kilometers (220 miles) north of Gao.

"We want to give France a heads-up and to tell them that they are allowing a situation to take place in Kidal that we do not understand," Yoro said. "We want France to tell us what they are up to because we are confused when they say on the one hand that Kidal is part of Mali, and at the same time, they act as if it doesn't belong to Mali."

Yoro, who was a member of the committee that organized the sit-in, said: "It's true that France liberated us, but at the same time we don't want to be taken advantage of."

The organizers of the early morning protest Thursday said more than 1,000 people participated, though officials said the number of people protesting was significantly less.

The protesters accuse France of long having given preferential treatment to the Tuaregs, a minority ethnic group whose members are predominantly from the country's north, a zone they refer to as the Azawad in the Tamashek language. Last year, the NMLA, made up of secular Tuaregs demanding independence, swept across the north, seizing towns and villages and briefly proclaiming the birth of a new Tuareg nation. They were swiftly kicked out by Islamic militants, who rode their coattails into the towns, only to then turn on their former allies, yanking down their multi-colored flags in order to replace them with the black flag of extreme Islam.

France, Mali's former colonial ruler, was greeted in Gao with shouts of "Vive la France" when they liberated the city on Jan. 26, and the scenes of exuberance were repeated throughout the northern towns they freed. With one major exception: Kidal.

The northernmost provincial capital has long been a Tuareg stronghold, and when French special forces entered the city they weren't accompanied by the Malian military. Nearly five months later, Malian soldiers have yet to step foot in Kidal. While the country's army has not been able to return, the NMLA was soon able to come back to Kidal. The protesters on Thursday accused France, which has a unit stationed at the Kidal airport, of simply looking the other way when the rebels returned.

Those gathered in the square also took issue with the Tuareg soldiers, who are part of a Tuareg battalion in the army, now patrolling Gao. The colonel leading the battalion defected during the events of 2012 and eventually went into exile along with his fighters in neighboring Niger. Col. Elhadji Gamou's brigade is now back in Gao, patrolling the streets. Civilians who are mostly from the darker-skinned, sub-Saharan ethnic groups accuse the Tuaregs of having shown complicity toward the Islamic extremists.

"We are here to denounce the presence of the Tuaregs in Gao. The soldiers loyal to Col. Gamou are doing everything they can to make the Tuaregs return in great numbers and we are not OK with this. We suffered for many months here in Gao because of them," said Atayoubou Agaly Maiga, a member of one of Gao's self-defense groups which were created to ferret out the members of extremist groups hiding among the population after their ouster by the French.

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Callimachi contributed to this report from Dakar, Senegal.

The 76-year-old Francis, who walks with a slight limp because of apparent lower back pain, paused several times in prayer during the 45-minute nighttime walk between St. John Lateran and St. Mary Major.

Thousands of pilgrims holding candles lined the route on a chilly spring evening.

During his nearly eight-year pontificate, Pope Benedict XVI would make the annual Corpus Domini procession riding on a specially outfitted flat-top pickup truck, kneeling in prayer. Pope John Paul II did the same in his final years.

On Thursday, two priests knelt on the truck in prayer before the Eucharist while Francis walked behind them.

President Barack Obama underlined Tuesday that investigators do not know if the twin bombing the day before that killed three people and wounded more than 170 was carried out by an international organization, a domestic group or a "malevolent individual." There has been no claim of responsibility.

A person briefed on the investigation told The Associated Press that the explosives were fashioned out of pressure cookers and packed with shards of metal, nails and ball bearings to inflict maximum carnage.

The relative ease of constructing such bombs and the powerful punch they deliver has made them attractive to insurgents and Islamic extremists, particularly in South Asia. They have turned up in past bombing plots by Islamic extremists in the West, including a plan by a U.S. soldier to blow up a restaurant frequented by fellow soldiers outside Fort Hood, in Texas. One of the three devices used in the May 2010 Times Square attempted bombing was a pressure cooker, according to a joint FBI and Homeland Security intelligence report issued in July 2010.

Al-Qaida's branch in Yemen gave a detailed description on how to make a pressure cooker bomb in the 2010 first issue of "Inspire," its magazine that only appears online, in a chapter titled "Make a bomb in the kitchen of your mom."

"The pressurized cooker is the most effective method" for making a simple bomb, the article said, describing how to fill the cooker with shrapnel and gunpowder and to create a detonator using the filament of a light bulb and a clock timer.

"Inspire" magazine has a running series of such training articles called "Open Source Jihad," which the group calls a resource manual for individual extremists to carry out attacks against the enemies of jihad, including the U.S. and its allies.The magazine is targeted heavily at encouraging "lone wolf" jihadis.

An issue last year reprinted an older article by a veteran Syrian jihadi Abu Musab al-Souri addressing would-be jihadis proposing a long list of possible targets for attacks, among them "crowded sports arenas" and "annual social events."

Notably, Army Pfc. Naser Jason Abdo, who was convicted and sentenced to life in prison last year for the Fort Hood restaurant bombing plot, was discovered to have a copy of the "How to build a bomb in the kitchen of your mom" article, according to the FBI. Investigators found bombmaking materials in his hotel that included a pressure cooker and gunpowder, according to testimony at his trial.

The SITE Monitoring Service, a U.S. independent group tracking militant messaging online, noted that Islamic extremists are not the only ones paying attention to the al-Qaida magazine: White supremacists have also circulated copies on their web forums. They found "Inspire" and "other al-Qaida manuals beneficial for their strategies," it said.

Over the course of 10 issues the past three years, "Inspire" has given detailed instructions with diagrams and photos on how to use automatic weapons, produce remote control detonators, set fire to a building or create forest fires. In the most recent issue, put out in March, it described how to set fire to a parked vehicle and how to cause road accidents with oil slicks on a road or tire-bursting spikes.

The chapters, including the one on pressure cooker bombs, were compiled into a booklet titled "The Lone Mujahed Pocketbook," released on Islamic militant web sites in March, according to SITE.

Al-Qaida's Yemeni branch, known as al-Qaida in the Arabian Peninsula, has repeatedly tried to carry out direct attacks on U.S. soil, once by dispatching the would-be 2009 Christmas bomber of a U.S. jet whose attack failed when the explosives hidden in his underwear failed to go off and then the following year by trying to mail explosives to the U.S. in packages that were intercepted.

The pressure cooker bomb's most frequent use seems to be in Afghanistan, Pakistan, Nepal and India in attacks against police or the public. This year, local press reports in Pakistan have reported several such bombs found planted on streets, including in the city of Karachi, where multiple militant groups operate.

In 2010, suspected militants attacked the U.S.-based Christian aid group World Vision in northwestern Pakistan, killing six Pakistani employees with a remotely detonated pressure cooker bomb.

That same year, the U.S. Department of Homeland Security put out a warning about such explosives, noting their frequent use in South Asia.

"The presence of a pressure cooker in an unusual location such as a building lobby or busy street corner should be treated as suspicious," it said.

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AP correspondents Cassandra Vinograd and Paisley Dodds in London and Eileen Sullivan in Washington contributed to this report.

The online blueprints for a fully functional 3D-printed gun have disappeared faster than a speeding bullet.

On Wednesday, the State Department ordered the company that posted the schematics, Defense Distributed, to remove them from the web. (Watch a Defense Distributed video explaining the gun above.) According to the State Department, publicly posting the instructions may have violated the International Traffic in Arms Regulations (ITAR), which governs the "transfer of, and access to" certain weapons and their technical details. By posting the files to the web where anyone in the world could download them, the company may have inadvertently violated those export restrictions.

"Please note that disclosing (including oral or visual disclosure) or transferring technical data to a foreign person, whether in the United States or abroad, is considered an export," the State Department  in a letter.

However, the State Department did not say that the instructions must remain offline for good. Rather, the department asked that Defense Distributed file the necessary paperwork for the government to determine if the blueprints are, in fact, a violation of ITAR. In the meantime, State wrote, the company "should treat the above technical data as ITAR-controlled."

That letter came just two days after Defense Distributed, through its open-source printing project DEFCAD, posted the instructions for its "Liberator" handgun to the Internet. In just three days, the instructions had already been downloaded more than 

Here's how it works, :

Fifteen of the gun's 16 pieces are constructed on the $8,000 Stratasys Dimension SST 3D printer, Forbes said. The final piece is a common nail, used as a firing pin, that can be found in a hardware store. []

And indeed, by Thursday evening, the webpage to download the instructions had been updated with the : "This file has been removed from public access at the request of the US Department of Defense Trade Controls. Until further notice, the United States government claims control of the information."

Still, the federal order does not mean all copies of the blueprints have been be wiped from the web. The instructions have been posted to the file-sharing sites Pirate Bay and Mega, among others, meaning they're still available for download.

Wilson, who claims to have been inspired by anarchist writings, himself made that point in an , saying he thought he would ultimately be free from the government's oversight.

"I still think we win in the end," he said. "Because the files are all over the Internet, the Pirate Bay has it to think this can be stopped in any meaningful way is to misunderstand what the future of distributive technologies is about."

Lawmakers at the state and federal level have already moved to ban printable firearms.

In California, Democratic state Senator Leland Yee said in athat he would soon introduce a bill to ban weapons that "are invisible to metal detectors and that can be easily made without a background check." At the federal level, Rep. Steve Israel (D-N.Y.) and Sen. Chuck Schumer (D-N.Y.) have likewise called for legislation to ban such firearms.

"A terrorist, someone who's mentally ill, a spousal abuser, a felon can essentially open a gun factory in their garage," Schumer

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