LOS ANGELES (TheWrap.com) - Co-writer-director Joseph Kosinski ("TRON: Legacy") digs all the way to the back of the refrigerator for "Oblivion," taking leftover bits of "The Matrix," "WALL-E," "2001," "Moon" and "Planet of the Apes," among countless other science-fiction classics, and putting them into a slick, shiny and state-of-the-art crock pot.

The results looks amazing, but most of the ideas that resonate will feel very familiar and more than a bit warmed-over.

You'll see one if not both of the movie's big twists coming, and while a case could be made that "Oblivion" will make the boldest anti-drones statement of any fictional film this year, it's a chilly movie that never draws you in enough to get fully invested in what's happening.

Tom Cruise opens the film with a head-spinning torrent of exposition, but it boils down to this: It's 2077. Sixty years earlier, alien invaders wrecked the moon, destroying much of Earth. What was left of the planet got trashed by nukes used to fight off the E.T.s, and now most of the population lives on a moon of Saturn.

The only people left on Earth are Jack (Cruise) and Victoria (Andrea Riseborough, "W.E."), who live in a high-tech house in the clouds and whose memories were wiped five years earlier.

He goes out every day to repair the drones that scan the earth for the remnants of the alien Scavengers; she reports their progress to Sally (Melissa Leo, with a ludicrous twang) at Mission Control. Unbeknownst to Victoria, Jack still remembers meeting up with a mystery woman (Olga Kurylenko of "To the Wonder") at the Empire State Building back before the war.

He's also built a secret hideaway in the mountains, a lakeside cabin where he can shoot hoops, listen to old vinyl LPs and squirrel away the books he has found in his travels.

One day, Jack happens upon the top of the Empire State Building, which the Scavengers are using as a homing beacon; following the coordinates being sent out, he finds a crashed spaceship, but the passengers aren't aliens - they're humans. And one of them is the lady from Jack's dreams.

This discovery sets in motion Jack's new understanding of who he is and what has happened to Earth, and "Oblivion" might have worked better if it weren't so proud of these revelations that most audience members will figure out long before the characters do.

Kosinski is great with the doohickeys - Jack's transport, his fold-up motorcycle, that house of the future - but neither the plot nor the characters click the way they should. (And I say that as someone who actually liked "TRON: Legacy.")

Cruise has to spend most of the film playing a literal blank slate, but even after he starts filling in his own memories, the character remains as vague as ever. And poor Morgan Freeman, who turns up late in the film, gets saddled with some astonishingly clichd dialogue. (That YouTube reel of characters in dozens of movies saying the line, "You look like shit," just got three seconds longer.) M83's score is mostly effective, but even it feels unoriginal, like the love child of Daft Punk's "TRON: Legacy" music and the "Inception" BWAAAAH.

There's a weirdly sexist tinge as well, with the female characters being either nefarious or inert (not to mention a triangular big bad alien presence that could have been designed by Judy Chicago). "Oblivion" also indulges in one of those have-your-cake endings that are so popular of late; not to give anything away, but this is another movie that promises a gutsy, powerful denouement only to give the audience a reassuring wink and a high-five.

The stink of studio notes and focus groups pervades throughout, in fact - that awkward narration at the beginning shares information that Jack offers up again later in the film; one imagines a test audience complaining that they didn't understand what was happening, and the studio deciding to overlay all that clunky exposition up front. Just a theory, but I'd put five bucks on it.

If the dialogue and the concepts of "Oblivion" had been as fresh and powerful as its art direction, we'd really have something here. Instead, it's something borrowed packaged inside something new.

So: if you've got questions about the HTC One, or about the wild smartphone market in general, there's no better place to be than right here, starting at 1:30 PM sharp on Monday. Ask us absolutely anything, and we'll do our best to answer.

The latest salvo came a day after China's foreign ministry dismissed as groundless a Pentagon report which accused China for the first time of trying to break into U.S. defense computer networks.

The Pentagon also cited progress in Beijing's effort to develop advanced-technology stealth aircraft and build an aircraft carrier fleet to project power further offshore.

The People's Liberation Army Daily called the report a "gross interference in China's internal affairs".

"Promoting the 'China military threat theory' can sow discord between China and other countries, especially its relationship with its neighboring countries, to contain China and profit from it," the newspaper said in a commentary that was carried on China's Defense Ministry's website.

The United States is "trumpeting China's military threat to promote its domestic interests groups and arms dealers", the newspaper said, adding that it expects "U.S. arms manufacturers are gearing up to start counting their money".

The remarks in the newspaper underscore the escalating mistrust between China and the United States over hacking, now a top point of contention between Washington and Beijing.

A U.S. computer security company, Mandiant, said in February a secretive Chinese military unit was likely behind a series of hacking attacks that targeted the United States and stole data from more than 100 companies.

That set off a war of words between Washington and Beijing.

China has said repeatedly that it does not condone hacking and is the victim of hacking attacks -- most of which it claims come from the United States.

"As we all know, the United States is the real 'hacking empire' and has an extensive espionage network," the People's Daily, a newspaper regarded as a mouthpiece of the Chinese Communist Party, said in a commentary.

The article -- which was published under the pen name "Zhong Sheng", meaning "Voice of China" -- said "in recent years, the United States has continued to strengthen its network tools for political subversion against other countries".

"Cyber weapons are more frightening than nuclear weapons," the People's Daily said. "To establish military hegemony on the Internet by repeatedly smearing other countries is a dangerous and wrong path to take and will ultimately end up in shooting themselves in the foot."

(Reporting by Sui-Lee Wee; Editing by Michael Perry)

Randi Weingarten, president of the American Federation of Teachers, called for a moratorium on penalties associated with tests aligned to the national standards called Common Core benchmarks until the standards have been fully implemented.

"The fact that the changes are being made nationwide without anything close to adequate preparation is a failure of leadership, a sign of a broken accountability system and, worse, and an abdication of our responsibility to kids, particularly poor kids," Weingarten told the Association for a Better New York, a business group.

Forty-five states and the District of Columbia have adopted the Common Core standards.

The issue in New York, among the first states to test students based on the standards, has been contentious. New York students in grades 3 through 8 took Common Core-aligned math and English tests during the last two weeks although most schools in the state have not fully implemented the standards.

Some New York students complained that the Common Core-aligned English tests were too difficult to complete in the allotted time, and there were reports of students crying from stress.

Weingarten said she supports the Common Core standards, which are intended to increase rigor and prepare students better for college and careers, but she urged New York not to evaluate teachers or students based on this year's tests.

"Across the state, scores from this spring's assessments may be used to determine whether students advance or are held back, to designate a school's performance, and even to determine whether schools stay open or shut down. And they will be used as 20 percent of teacher evaluations," she said.

Merryl Tisch, the head of New York's Board of Regents, said the same percentage of teachers will be rated "effective" based on this year's tests as in the past. But she noted the state Education Department has said it will not designate any schools as failing based on the tests.

She added: "We believe strongly that this is the right thing for students and teachers right now."

Andrew Kirtzman, a spokesman for the city Department of Education, said, "This is about a special interest that doesn't want this to happen because of fear for their jobs."

The AFT says it has 1.5 million members. The National Education Association claims to be the largest teachers union with 3 million members.

In a message posted on YouTube, Abou Obeida Youssef Al-Annabi, a notable in the Al-Qaida in the Islamic Maghreb group, or AQIM, said the "crusade" led by France in Mali makes its interests "legitimate targets."

French President Francois Hollande said he takes the threat seriously.Hollande ordered the Jan. 11 intervention to stamp out AQIM and two other groups of radicals that controlled northern Mali.

The speech by Al-Annabi said the military campaign against AQIM "is an issue of religion being disgraced and a people being annihilated and an identity destroyed." He said, "It is an obligation on you, Muslims, to respond ... by confronting French interests everywhere."

"These interests," Al-Annabi said, "have become legitimate targets for you," warning that France risks falling into "the same swamp which America fell in in Iraq and Afghanistan."

The group had previously threatened French interests but in less dramatic written statements.

France, helped by African forces, quickly pushed AQIM and other jihadists from Mali's main northern cities, including Timbuktu, killing or dispersing jihadists.Special forces and other troops are now in a clean-up phase, searching for scattered fighters and their caches after seizing some 200 tons of munitions and arms.

"We take seriously this threat from AQIM. We have inflicted tremendous loss to AQIM via the intervention in Mali," Hollande said at a news conference."But AQIM networks exist outside Mali," he noted.

The intervention in Mali will continue "for the time required," Hollande said, while France remains vigilant elsewhere, including protecting French installations.

He noted the April 23 car bomb outside the French Embassy in Tripoli, the Libyan capital, that wounded two French guards and a Libyan girl in a home nearby. No group claimed responsibility for that attack.

French authorities have said they were increasing security around Africa's Sahel region where Mali, a former colony, is located as well as in the Middle East.In France, there is extra surveillance at monuments and facilities that draw the public such as airports.

France has nearly 4,000 troops in Mali. They have been joined by African forces, including from Chad, and soldiers from other African nations are being trained to replace French forces as they make a staggered departure. However, French authorities have said that there will still be 1,000 troops in Mali by the end of the year, along with U.N. peacekeeper, as the nation prepares for presidential elections, perhaps as early as July.

AQIM emerged in 2006 from a previous movement of radical Algerian insurgents, and bit by bit spread its extremism around a large area of the Sahara. By last year it reigned over northern Mali.

---

Maamoun Youssef in Cairo contributed to this report.

Follow Ganley on Twitter at http://www.twitter.com/Elaine_Ganley

MADRID (Reuters) - Real Madrid coach Jose Mourinho has refused to tone down his rhetoric in response to a call from club president Florentino Perez for unity in an obviously divided dressing room during the final few weeks of the season.

After some unsavoury sniping between Mourinho and members of his squad in recent weeks, Perez made a rare foray into the limelight on Monday when he called for the club to be "united for the fans" as they prepare for this month's King's Cup final against city rivals Atletico Madrid and seek to secure second place in La Liga.

Mourinho raised eyebrows on Friday when he made a thinly veiled attack on goalkeeper Iker Casillas, whom he has dropped in favour of Diego Lopez, prompting club heavyweights Sergio Ramos and Pepe to speak out in support of their captain.

The sense that all is not well has been heightened by speculation that Mourinho is poised to leave at the end of the season and the outspoken Portuguese has said little to contradict reports he is on his way back to Chelsea.

At a news conference on Tuesday previewing Wednesday's La Liga match at home to Malaga, he responded to Portuguese compatriot Pepe's expression of support for Casillas, made after Saturday's 4-3 La Liga victory at home to Real Valladolid.

Pepe had spoken out because he was frustrated that team mate Raphael Varane had edged ahead of him in the pecking order to partner Ramos in central defence, Mourinho said.

"You just have to be a normal person like me or like almost everyone in this room to know that we are talking about frustration," he said.

"His problem has a name: Raphael Varane. It's not easy for a man of 31 years, with status and history, to be trampled over by a kid of 19.

"But that's the law of life. On a sporting level Pepe's life has changed.

"I have no problem with him. I understand that it's not an easy situation but I have to try to be honest and I think that there are very few people who don't think that the future of Real Madrid in defence is Varane with Sergio Ramos."

CERTAIN RESPONSIBILITIES

Asked about his relationship with Casillas, Mourinho reiterated that he believed Lopez, who was brought in ostensibly as cover when Casillas broke a bone in his hand in January, was the better keeper.

Casillas has been Real and Spain keeper for more than a decade and is a hero to fans of the club and the national team.

"Let's see if you understand it once and for all, I am a soccer coach," Mourinho told reporters.

"They hired me to be a soccer coach and a soccer coach has certain responsibilities, one of which is to pick the team.

"I don't do it by flipping a coin. I do it after discussion and lengthy analysis of my decisions.

"For me, I like Diego Lopez better as a goalkeeper than Iker Casillas. I don't do it to harm anyone.

"I accept it if someone says that Casillas is better than Diego Lopez but you have to accept that I am the coach of Real Madrid."

Mourinho, who almost walked out of the news conference after repeated problems with the sound system, was again asked about his future at Real, where he has a contract until June 2016, and whether he was trying to provoke the club into sacking him so he could pocket a substantial payoff.

"So that there is absolutely no doubt, I want to say that I will earn a salary until the final day I work for Real Madrid," he said. "I don't want a single euro more."

If defending champions Real fail to beat Malaga on Wednesday, leaders Barcelona will have an unassailable lead and will secure their fifth La Liga title in four years.

SYDNEY, May 3 (Reuters) - The contest at the breakdown will be a "huge" part of the British and Irish Lions series and will need to be strictly managed by referees if the tests are to be any kind of spectacle, Australia coach Robbie Deans believes.

Neutral referees New Zealand's Chris Pollock, South African Craig Joubert and France's Romain Poite will officiate the three tests in June and July and Deans said they must take firm control of the tackle area.

"You look at World Cups, the ante goes up and the breakdown changes and the nature of the game changes and I suspect this will be no different," Deans told a small group of reporters this week.

"Just the adrenaline that'll be pumping through these blokes' veins, there's going to be a lot of pressure on the referees to manage that area.

"Because if that area isn't managed effectively, everyone's talking about the spectacle and so forth, there'll be no spectacle, you'll struggle to find the ball.

"You can only work in the circumstance that you're confronted with, so hopefully that will be an area that is adjudicated consistently and effectively.

"Otherwise it will just be ...," he petered off, making his point by banging his fists together.

Fortunately for Deans, he has no shortage of talent at openside flanker to contest the breakdown, even if his first choice David Pocock has been ruled out of the series by a knee injury.

"There's some class players," he said. "You look at that cluster of David Pocock, Michael Hooper and Liam Gill, they're almost three once-in-a-generation players.

"It's fantastic, and they're still young men so they've got a lot of rugby ahead of them."

Soon to be added to that pool is George Smith, who played all three tests in the 2001 series against the Lions and looks likely to be cleared by his Japanese club to feature again this year.

"He's just class," Deans said.

"When David Pocock turned up and we had the two of them I was really hopeful we were going to have them side-by-side, it would have been great for both of them because they'd both drive each other, but also give them respite because it's an area where there is a high attrition rate.

"But obviously at the time it was an understandable decision from George with a young family and four young kids and he wasn't seeing a lot of them with all the travel in the southern hemisphere.

"It worked out well for him and he's been lucky enough, it would appear, to come back and get a rare plum as well in a Lions series, so it's worked out well."

Although resources are slimmer at blindside flanker, Scott Higginbotham has been in fine form for the Melbourne Rebels filling in for Gareth Delve as captain and at number eight.

"Scotty's responding really well to captaincy," said Deans.

"You can't ask something of people around you if you are not up for it yourself.

"That's brought a real consistency to his approach to the game and it's probably stimulated him to be fair.

"It's got him thinking about what's important."

Higginbotham's selection at number six for the test side ahead of more workmanlike candidates like Dave Dennis would indicate that Australia will be adopting an expansive style of play.

Deans said the Wallabies "had to" look to their traditional strengths if they were to beat the Lions but fans should not expect his team to run the ball from every opportunity.

"That's the way you remember it when you win," he laughed. "(But) there'll be ball movement, don't worry about that." (Editing by Greg Stutchbury)

WASHINGTON (Reuters) - As Congress sifts through a growing number of requests for targeted relief from automatic spending cuts in coming weeks, advocates seeking funding shifts likely will need to tell a compelling story with potential life-or-death consequences.

Requests without such a strong selling point may find it impossible to gain enough bipartisan support as lawmakers vow not to repeat a swift and controversial action last week to save airline travelers from flight delays caused by automatic "sequestration" spending cuts.

Congress was worried about a toxic public backlash when it moved quickly to allow the Federal Aviation Administration to use some airport improvement funds to pay salaries of air traffic controllers, ending furloughs that had delayed thousands of flights across the country.

When members of Congress return from a recess on Monday, there will be no shortage of other requests to shift funds from other budget accounts awaiting them.

The National Park Service faces closures and cutbacks that will cost jobs in communities that depend on the parks as the summer travel season begins. Some 70,000 children may be shut out of the Head Start preschool program for low-income families while funding for Meals on Wheels, cancer research and some treatments for Medicare patients will be cut.

The Pentagon is expected to ask for more authority to move up to $7.5 billion within its budget to cover costs for training and military operations in Afghanistan. With troops still in harm's way, that request likely will face few objections.

More needs will pile up As the across-the-board spending cuts - $85 billion through September 30 - take hold. But most will fall on deaf ears as lawmakers insist that a comprehensive budget deal is needed to resolve sequester cuts, not individual fixes.

"With the possible exception of life-threatening issues, there will be plenty of pleas from people who represent worthy causes that get ignored," said Greg Valliere, chief political strategist at Potomac Research, an investment consulting firm.

"It's extremely unlikely that House Republicans will be willing to grant exceptions for national parks, Meals on Wheels or teachers," he said.

The sequester cuts that took effect March 1 were conceived in 2011 as a way to force the White House and Congress to find an alternative budget deal rather than have spending cuts kick in automatically. Policymakers failed to reach such an agreement and now must deal with the fallout from the cuts, which total will total $1.2 trillion over 10 years unless replaced.

Last month's flight delays created a mix of pressure from the airline industry and constituents facing a universally loathed problem that both parties could rally around.

Senate Majority Leader Harry Reid, however, is not inclined to pursue additional one-off measures to deal with sequester, a Democratic leadership aide said. Reid would prefer to press forward with his proposal to simply delay the cuts through September 30 in order to buy more time for a broader budget deal.

"I just don't see another one-off bill that's going to rise to the same level as flight delays," a senior House Republican aide said.

Many House Republicans also are concerned about giving the Obama administration more authority to move money between budget accounts at federal agencies, which circumvents Congress' constitutional powers to direct spending.

In the case of the Department of Health and Human Services, the Republican aide said there is concern that such budget shifts could inadvertently give the agency power to help fund implementation of Obama's healthcare reform law, which many Republicans deeply despise and want to repeal.

SAY NO TO CANCER PATIENTS?

But funding cutbacks for some Medicare cancer treatments and cancer research studies also could be difficult for many lawmakers to resist.

The most concerted effort in this area is a Republican House bill that would exempt Medicare reimbursements on expensive cancer drugs administered at doctors' offices and clinics - one of the few portions of the healthcare program for the elderly that is subject to the sequester. The Centers for Medicare and Medicaid Services (CMS) would have to shift cuts in these reimbursement rates elsewhere under the measure.

The bill's author, Representative Renee Ellmers of North Carolina, a Tea Party favorite, argues that because of the sequester, oncology clinics have been sending patients to hospitals to get their drugs.

But hospital treatment costs, which are not subject to sequester, are far higher - an average increase of $6,500 per patient per year, according to one study. Ellmers argues that this circumvents the whole point of sequester spending cuts.

"We don't want to see treatments delayed, and some patients on fixed incomes might skip treatment altogether if they are forced to go across town to a hospital," said Ellmers, who spent two decades as a surgical nurse before winning a seat in Congress in 2010.

The measure has substantial bipartisan support, with 51 cosponsors including 11 Democrats. Separately, 124 House members from both parties signed a letter to the CMS director asking that "any available flexibility be used to direct the cuts away from patients."

A spokesman for House Speaker John Boehner declined to comment on the bill's prospects for passage, referring questions about it to the House Energy and Commerce Committee.

THREAT TO CANCER TRIALS

Cancer research doctors also say further sequester funding cutbacks could ultimately cost lives.

Dr. Scott Lippman, director of the University of California-San Diego Moores Cancer Center, said the sequester will mean fewer clinical trials for promising therapies, and some patients ultimately will be turned away from these trials. Research on new treatments also could be slowed.

"This going to harm patients," Lippman said. "This is going to prevent patients from getting treatments that could save their lives."

At a time when advancements in cancer research are moving very quickly with new gene-based discoveries, he said now is "not the time to be slamming on the brakes."

While no trials have been canceled yet due to sequester alone, research centers are working hard to try to cut everything else that they can, said Dr. Edward Partridge, director of the University of Alabama-Birmingham's Comprehensive Cancer Center. But the choices will be difficult.

"We will do everything we can to maintain our current clinical trial volume," he said. "Even if it's at the expense of new discovery. I hope (sequester) doesn't last too long so that we have to withdraw the possibility of clinical trials for patients. That would be a disaster."

(Reporting By David Lawder; Editing by Fred Barbash and Bill Trott)

It has since eased those worries.

On Wednesday the world's biggest social networking company said nearly a third of its advertising revenue came from mobile in the first three months of the year, helping to push total revenue up 38 percent to surpass Wall Street's expectations.

"They are making the transition to mobile faster than anyone anticipated," said Sterne Agee analyst Arvind Bhatia. "It seems like they are delivering."

Facebook Inc. said Wednesday that its net income was $219 million, or 9 cents per share, in the January-March period. That's up from $205 million, or 9 cents per share, in the same period a year ago, when it was still private.

Revenue grew to $1.46 billion from $1.06 billion, above analysts' expectations of $1.44 billion.

Excluding special items, mainly related to stock compensation expenses, Facebook earned 12 cents per share, matching the average of analyst expectations, according to FactSet.

Menlo Park, Calif.-based Facebook said that its mobile advertising revenue was 30 percent of its total ad revenue in the first quarter, amounting to $375 million. That's up from 23 percent, or $306 million, in the fourth quarter. In the third quarter the first time it disclosed such figures the company generated 14 percent, or $153 million, of its advertising revenue from mobile.

Investors had been worried about Facebook's ability to grow mobile revenue since before its initial public offering in May 2012. That's because although the number of people who access Facebook on smartphones and tablet computers has been growing quickly, Facebook didn't begin showing ads to those users until last year.

David Ebersman, Facebook's chief financial officer, said most advertisers did not specify that their ads be shown only on desktop computers or only on mobile devices, "rather they put their ads into our system and allow us to show the ads on whatever device where the ads will perform best."

Bhatia thinks Facebook will fare even better on mobile devices once Zuckerberg firms up its plan to make money from the growing audience checking into Instagram, a photo-sharing service that the company bought last year for $521 million. The analyst believes Instagram will play a bigger role in Facebook's business next year.

Wedbush analyst Michael Pachter said the results are likely to quiet skeptics who doubted Facebook's ability to mine its growing mobile traffic for revenue. He was particularly impressed by the 23 percent increase in Facebook's mobile ad revenue, even though the company's overall ad revenue for the period dipped 6 percent from the final three months of last year.

"Their mobile business is probably bigger than any mobile business on the planet other than the (wireless telecommunications) carriers and Google," Pachter said.

Facebook started showing mobile advertisements in early 2012. In the third quarter of last year, the company generated 14 percent, or $153 million of its advertising revenue from mobile. In the fourth quarter mobile ads represented to 23 percent, or $306 million.

Research firm eMarketer says Facebook's share of the U.S. online advertising market is growing. This year, the company is expected to take a 6.5 percent share of U.S. online ad spending, up from 5.9 percent in 2012. Still, that figure is far behind Google Inc.'s 41.6 percent.

On the mobile front, eMarketer expects Facebook to take a 13.2 percent share of U.S. ad revenue, up from 9.5 percent in 2012, the first year it made any money from mobile ads. Though Facebook is No. 2, it is far behind Google in U.S. mobile advertising. EMarketer expects the online search leader to take a 54.7 percent share of U.S. mobile advertising revenue this year.

The company also grew its user base during the quarter. This has also been an area of some concern to investors amid chatter of "Facebook fatigue," especially among younger users, surfacing in recent months. But Facebook said its monthly user base grew to 1.11 billion accounts as of the end of March, up 5 percent from 1.06 million at the end of December.

The number of users who access Facebook every day, on average, grew 8 percent to 665 million in March, from 618 million in December.

Gartner Inc. analyst Brian Blau said the ongoing growth of daily users suggests that the service is a tough habit to break.

"The network remains in full force," Blau said. "You have to give them a lot of credit."

That doesn't mean there won't be concerns about some Facebook users, especially teenagers, migrating to other mobile applications and digital outlets to hang out with friends and share slices of their lives, said Forrester Research analyst Nate Elliott.

"There is always going to be something new in social," Elliott said. "The question is how much of it is a threat to Facebook? All Facebook can do is keep those users coming back and make money off those users. And Facebook seems to be doing both of those things reasonably well."

Instagram now has 100 million monthly users, up from 22 million when Facebook agreed to buy the company in April 2012.

Facebook's stock rose 12 cents to $27.55 in after-hours trading. The stock closed down 34 cents on Wednesday. It is up 3 percent since the beginning of the year compared with an 11 percent increase for the Standard & Poor's 500 index. Facebook went public on May 18, 2012, at $38 per share, a price it hasn't hit since.

__

AP Technology Writer Michael Liedtke in San Francisco contributed to this story.

LONDON (Reuters) - The new strain of bird flu that has killed 17 people in China has been circulating widely "under the radar" and has acquired significant genetic diversity that makes it more of a threat, scientists said on Friday.

Dutch and Chinese researchers who analyzed genetic data from seven samples of the new H7N9 strain say it has already acquired similar levels of genetic diversity as much larger outbreaks of other H7 strains of flu seen previously in birds.

"The diversity we see in these first few samples from China is as great as the diversity we have seen with a large outbreak in the Netherlands several years ago and one in Italy," said Marion Koopmans, head of virology at the Dutch National Institute for Public Health and the Environment, who worked on the study as part of a nine-member team.

"This means it (the H7N9 strain in China) has been spreading quite a bit and it's important to understand where exactly that is going on."

Its genetic diversity shows the virus has an ability to mutate repeatedly and is likely to continue doing so, raising the risk that it may become transmissible among humans.

Koopmans, whose research was published in the online journal Eurosurveillance, said the circulation would probably have taken place in either birds or mammals, but said exactly which animals were involved was not yet clear.

"Simply the fact that this virus is spreading under the radar - because that is what this data confirms - is of concern," she told Reuters in a telephone interview.

The H7N9 virus is so far known to have infected 87 people in China, killing 17 of them. Health officials raised further questions on Friday about the source of the new strain after data indicated that more than half of patients had had no contact with poultry.

MUTATIONS

A scientific study published last week showed the H7N9 strain was a so-called "triple reassortant" virus with a mixture of genes from three other flu strains found in birds in Asia. One of those three strains is thought to have come from a brambling, a type of small wild bird.

For their study, Koopmans and her team compared some data from the first two weeks of the China H7N9 outbreak with data from a large H7N7 flu outbreak in birds and people the Netherlands in 2003 and an H7N1 epidemic in birds in Italy in 1999 and 2000.

The Dutch outbreak resulted in infection of poultry on 255 farms and led to the culling of about 30 million chickens. Some 89 people were also diagnosed as having the H7N7 virus and one person, a vet, died as a result of the infection.

The comparison suggested that "widespread circulation (of the H7N9 strain in China) must have occurred, resulting in major genetic diversification", the researchers wrote in their study.

They added: "Such diversification is of concern, given that several markers associated with increased risk for public health are already present."

Flu experts in China and at the World Health Organization say there is no evidence so far that H7N9 is passing easily between people.

But scientists who analyzed the genetic sequence data from three early samples from China say the virus has already acquired some mutations that might make it more likely to be able to do so in the future, raising the risk of a human pandemic.

"Although human infections with H7 influenza viruses have occurred repeatedly over the last decades without evidence of sustained human-to-human transmission, the absence of sustained human-to-human transmission of H7N9 viruses does not come with any guarantee," Koopmans' team wrote in their study.

(Editing by Ben Hirschler and Alison Williams)