The U.S. is developing aircraft carrier-based drones that could provide a crucial edge as it tries to counter China's military rise.

American officials have been tightlipped about where the unmanned armed planes might be used, but a top Navy officer has told The Associated Press that some would likely be deployed in Asia.

"They will play an integral role in our future operations in this region," predicted Vice Adm. Scott Van Buskirk, commander of the U.S. 7th Fleet, which covers most of the Pacific and Indian oceans.

Land-based drones are in wide use in the war in Afghanistan, but sea-based versions will take several more years to develop. Northrop Grumman conducted a first-ever test flight _ still on land _ earlier this year.

Van Buskirk didn't mention China specifically, but military analysts agree the drones could offset some of China's recent advances, notably its work on a "carrier-killer" missile.

"Chinese military modernization is the major long-term threat that the U.S. must prepare for in the Asia-Pacific region, and robotic vehicles _ aerial and subsurface _ are increasingly critical to countering that potential threat," said Patrick Cronin, a senior analyst with the Washington-based Center for New American Security.

China is decades away from building a military as strong as America's, but it is developing air, naval and missile capabilities that could challenge U.S. supremacy in the Pacific _ and with it, America's ability to protect important shipping lanes and allies such as Japan and South Korea.

China maintains it does not have offensive intentions and is only protecting its own interests: The shipping lanes are also vital to China's export-dependent economy. There are potential flash points, though, notably Taiwan and clusters of tiny islands that both China and other Asian nations claim as their territory.

The U.S. Navy's pursuit of drones is a recognition of the need for new weapons and strategies to deal not only with China but a changing military landscape generally.

"Carrier-based unmanned aircraft systems have tremendous potential, especially in increasing the range and persistence of our intelligence, surveillance and reconnaissance operations, as well as our ability to strike targets quickly," Van Buskirk said at the 7th Fleet's headquarters in Yokosuka, Japan.

His fleet boasts one carrier _ the USS George Washington _ along with about 60 other ships and 40,000 sailors and Marines.

Experts say the drones could be used on any of the 11 U.S. carriers worldwide and are not being developed exclusively as a counterbalance to China.

But China's reported progress in missile development appears to make the need for them more urgent.

The DF 21D "carrier killer" missile is designed for launch from land with enough accuracy to hit a moving aircraft carrier at a distance of more than 900 miles (1,500 kilometers). Though still unproven _ and some analysts say overrated _ no other country has such a weapon.

Current Navy fighter jets can only operate about 500 nautical miles (900 kilometers) from a target, leaving a carrier within range of the Chinese missile.

Drones would have an unrefueled combat radius of 1,500 nautical miles (2,780 kilometers) and could remain airborne for 50 to 100 hours _ versus the 10 hour maximum for a pilot, according to a 2008 paper by analysts Tom Ehrhard and Robert Work at the Center for Strategic and Budgetary Assessments. Work is now an undersecretary of the Navy.

"Introducing a new aircraft that promises to let the strike group do its work from beyond the maximum effective firing range of the anti-ship ballistic missile _ or beyond its range entirely _ represents a considerable boost in defensive potential for the carrier strike group," said James Holmes of the U.S. Naval War College.

Northrop Grumman has a six-year, $635.8 million contract to develop two of the planes, with more acquisitions expected if they work. A prototype of its X-47B took a maiden 29-minute flight in February at Edwards Air Force Base in California. Initial testing on carriers is planned for 2013.

Other makers including Boeing and Lockheed are also in the game. General Atomics Aeronautical Systems, Inc. _ the maker of the Predator drones used in the Afghan war _ carried out wind tunnel tests in February. Spokeswoman Kimberly Kasitz said it was too early to divulge further details.

Some experts warn carrier-based drones are still untested and stress that Chinese advances have not rendered carriers obsolete.

"Drones, if they work, are just the next tech leap. As long as there is a need for tactical aviation launched from the sea, carriers will be useful weapons of war," said Michael McDevitt, a former commandant of the National War College in Washington, D.C., and a retired rear admiral whose commands included an aircraft carrier battle group.

Some analysts also note that China may be reluctant to instigate any fighting that could interfere with its trade.

Nan Li, an expert at the U.S. Naval War College's China Maritime Studies Institute, doubts China would try to attack a U.S. carrier.

"I am a skeptic of such an interpretation of Chinese strategy," he said. "But I do think the X-47B may still be a useful preventive capability for worst-case scenarios."

The Air Force and Navy both sponsored a project to develop carrier-based drones in the early 2000s, but the Air Force pulled out in 2005, leaving the Navy to fund the research.

Adm. Gary Roughhead, chief of naval operations, said last summer that the current goal of getting a handful of unmanned bombers in action by 2018 is "too damn slow."

"Seriously, we've got to have a sense of urgency about getting this stuff out there," he told a conference. "It could fundamentally change how we think of naval aviation."