Is New China Stealth Fighter Rival to Troubled US F-22 Raptor?

Just as America's latest breed of super jet fighters are  being reigned in due to a mystery safety problem, a new Pentagon report released today notes that China's own version of a next-generation fighter appears to be designed to have similar capabilities.

"The January 2011 flight test of China's next-generation fighter prototype, the J-20, highlights China's ambition to produce a fighter aircraft that incorporates stealth attributes, advanced avionics, and super-cruise engines," said the Pentagon's 2012 annual  assessment of the Chinese military.

The report comes a month after a second prototype of the  J-2o was reportedly spotted rolling around a Chinese airfield, more than a year and a half since China's only other known prototype made its  first public flight.

The three attributes described by the Pentagon are among the advanced capabilities of the F-22 Raptor, the stealth fighter jet billed by the U.S. Air Force and its manufacturer, Lockheed Martin, as the most sophisticated fighter on the planet. But currently the entire fleet of F-22s, which cost the U.S. government an estimated $79 billion, has been slapped with strict flight restrictions due to safety concerns for pilots.

The restrictions, which keep the planes in close proximity to potential landing strips in case of a mid-air emergency, were announced two weeks after  an ABC News "Nightline" investigation found that the advanced $420 million-a-pop fighter jets have been plagued by a rare but potentially deadly oxygen problem for years. Despite multiple investigations including a four-month full-fleet grounding last year, the Air Force has been unable to pinpoint the cause.

READ: ABC News Investigation Into the F-22 Raptor

The concept of the F-22 itself has also been long debated. Officials at the Air Force and Lockheed Martin have said the jets are essential to the future of American war power. However, funding for new super jets was cut by Congress in 2009 after powerful critics from across the political spectrum, from Sen. John McCain (R.-Ariz.) to then Defense Secretary Robert Gates to President Barack Obama, all called on lawmakers to halt F-22 orders at 187 planes, saying that the plane was designed to fight fleets of other, rival next-generation fighters - an enemy that does not exist.

Despite going combat operational in late 2005, the jets have yet to go into combat, from Iraq and Afghanistan to the  "no-fly zone" over Libya last March. In all cases, the Air Force said the sophisticated fighters simply weren't needed.

READ: McCain Says $79 Billion F-22s Still Have No Mission

Just before funding for the F-22 was cut in 2009, President Obama received a letter from more than a dozen Congressmen and local lawmakers in support of the F-22. In the letter, the supporters claimed the full force of a 600-plus F-22 fleet would be needed to counter future rivals like Russia and China.

Since, both Russia and China appear to have developed prototypes for their own next generation fighters. The Russian variant, the  Sukhoi T-50, was shown off to the public during an air show last August. Russian news reports compared the jet's capabilities directly with those of the F-22. Though China is not believed to have more than a couple J-20s, a  U.S. government report on Chinese weapons systems released last month said U.S. intelligence estimated that at least some J-20s could go combat operational as soon as 2018.

That document, from the  U.S.-China Economic and Security Review Commission, revealed that some U.S. analysts doubt the Chinese are very far along in developing the "key components for designing a fifth-generation fighter" such as effective stealth technology and high-performance engines.

"We've got to continue to watch as it develops. It's still in the prototype phase," David Helvey, Acting Deputy Assistant Secretary of Defense for East Asia and Asia Pacific Security, told reporters today. "We'd like to be able to continue to monitor developments on that to understand exactly what China may intend to use it for and I wouldn't want to speculate at this point for what those specific missions might be."

In a  speech in 2009, Gates noted that other nations were developing next-generation fighters but said America is already way ahead in the numbers game and that gap "only widens" as the Air Force begins receiving hundreds of the F-22-s companion fighter, the  F-35 Joint Strike Fighter - a plane that has had its share of cost overruns and delays in development.

ABC News' Luis Martinez contributed to this report.