SINGAPORE — Will China's development of new weapons counter the dominance of U.S. forces in the Asia-Pacific region — in space, at sea and, most recently, in the air?

Photographs and video footage appeared on Chinese websites last week purporting to show China's first stealth fighter carrying out runway tests. A test flight of the twin-engine jet, known as the J-20, took place Tuesday, and Chinese military sources have been quoted as saying that the aircraft could be deployed as early as 2017.

Such a timetable would be a considerable advance on most assessments by foreign intelligence agencies. It follows a warning last month by a senior U.S. commander that China, again well ahead of expectations, had developed and started fielding a ballistic missile that may be capable of hitting a U.S. aircraft carriers and other big warships 1,500 km or more from the Chinese coastline.