By JEREMY PAGE
BEIJING—Images and witness accounts posted online Tuesday appeared to show that China's stealth fighter prototype had made its first test flight, even as Robert Gates, the U.S. Defense Secretary who has downplayed China's stealth aircraft capability, was meeting Chinese civilian leaders in Beijing.
The J-20, which has been undergoing runway tests for the last two weeks or so, took off from an airstrip at the Chengdu Aircraft Design Institute just before 1 p.m. local time and flew for about 20 minutes, according to several witness accounts posted by Chinese bloggers.
Photographs of the twin-engine plane in flight appeared on several unofficial Chinese defense-related websites, which have also posted dozens of still and video images of the J-20 making the runway tests over the last couple weeks.
Accounts of Tuesday's flight couldn't immediately be directly verified.
China's Defense Ministry, Air Force and the Chengdu Aircraft Design Institute have all declined to comment on previous J-20 images, and their spokespeople were not immediately available for further comment Tuesday.
Asked about the test flight at a routine briefing Tuesday, Ministry of Foreign Affairs spokesman Hong Lei didn't confirm or deny it had taken place. But he said that "as technology develops, and in accordance with the needs of national defense, it is natural for countries to upgrade their weapons equipment. The development of China's weapons equipment is completely based on the needs of its own security, and it is meant to protect China's sovereignty, security and territorial integrity. It is not aimed at any country or specific target."
Chinese authorities, who routinely delete politically sensitive material and detain those who produce it, have allowed the J-20 images to be circulated, in what military experts say is a clear sign that the People's Liberation Army wanted them made public.
The images and accounts of the apparent test flight Tuesday were also re-produced by xinhuanet.com, the more commercial arm of the state-run Xinhua news agency, and by huanqiu.com, the website of the state-run Global Times newspaper.
The images suggest that China is making faster-than-expected progress in developing a potential rival to the U.S. F-22—currently the world's only fully operational stealth fighter.
The timing of the test flight also appears to be designed to send a clear message that China is pressing ahead with its military modernization program despite growing concerns about it among the U.S. and its Asian allies.
That message undercuts the symbolism of Mr. Gates' visit, which is designed to smooth military relations ahead of a state visit to the U.S. next week by Chinese President Hu Jintao.
Mr. Gates arrived in Beijing Sunday on a three-day mission to deepen and stabilize military exchanges that China has repeatedly suspended for political reasons, most recently in January 2010 over U.S. arms sales to Taiwan.
But China's military appears to be doing the bare minimum to revive military ties and ensure Mr. Hu's visit goes smoothly, while at the same time showcasing its growing firepower before a domestic and international audience.
On Monday, Mr. Gates' Chinese counterpart, Gen. Liang Guanglie rebuffed a U.S. proposal for a clear timetable of deeper strategic defence talks, and made it clear that it would suspend military ties again if the U.S. sold more arms to Taiwan.
As word of Tuesday's test flight was surfacing Tuesday, Mr. Gates was holding meetings with Mr. Hu and Yang Jiechi, China's Foreign Minister.
During brief remarks together in front of reporters, neither Mr. Hu nor Mr. Gates mentioned the J-20. Mr. Hu said that the U.S. defense secretary's visit "will be very helpful in promoting mutual understanding and trust, and facilitate improvement and development of military-to-military relations between our two countries."
Mr. Gates thanked the Chinese leader and expressed "appreciation for the extraordinary hospitality of my Chinese hosts during this visit," which he said was helping advance the "long-term improvement" in the relationship between the U.S. and the Chinese military.
Pentagon officials had suggested that China's civilian leaders were more anxious than their military colleagues to stabilize defense relations. But even if that was the case, Tuesday's meetings have now been upstaged by the apparent test flight.
The message for Mr. Gates is also the more pointed as it was he who cut funding for the F-22 in 2009, predicting that China would not have any such planes by 2020 and only a handful by 2025.
A few months later, He Weirong, the deputy head of China's air force, announced that China's first stealth fighters were about to undergo test flights and would be deployed in "eight or 10 years."
U.S. defense and intelligence officials now say they expect China to start deploying the aircraft by around 2018.