The channel showed images of a prototype space fighter being assembled whose outward appearance was almost identical to a U.S. pilotless upper-atmosphere military spaceship, the X-37B, the daily said.

Hong Kong's Ming Pao daily on Tuesday said Shaanxi TV last Saturday quoted acting provincial governor Zhao Zhengyong as saying China has "succeeded in the test flight of a prototype aircraft that can fly through the atmospheric layer." Zhao was visiting a state-run aircraft corporation at Xi'an high-tech industrial development zone.

China is making progress in building an "upper-atmosphere" jet fighter, an official said last week, adding to a flurry of speculation about China's growing air power.

In April last year, the U.S. successfully tested the X-37B, which is about a quarter of the size of existing spacecraft.

The daily said China's development of the aircraft was leaked to the pres like recent stories about its new stealth fighter dubbed the J-20, but authorities were "deleting all Internet posts about the space fighter."

The Ming Pao and the Zhongguo Pinglun (China Review), a news website in Hong Kong, posted an article headlined "China succeeds in spacecraft test flight in tandem with U.S. X-37B" until early Tuesday, but no mainland Chinese media websites mentioned anything about it.

Meanwhile, U.S. Defense Secretary Robert Gates said that in a meeting with Chinese President Hu Jintao on Tuesday he expressed concerns about China's test flight of a prototype of the J-20 during his visit. But Hu assured him the timing is not related to his visit, he added.

China's official Xinhua news agency reported a J-20 took off around 12:50 p.m. and landed at 1:11 p.m. after a successful flight of about 18 minutes on Tuesday." It showed 23 stills of the fighter flying over an urban area or in maintenance.

Gates' visit achieved maximum exposure for the images. The U.S. defense secretary had earlier said the Chinese stealth fighter would not be ready until about 2020.