China 'preparing nuclear test'

China is preparing to carry out a small underground nuclear test, according to sources in Washington.

It is also believed the US surveillance aircraft which collided with a Chinese interceptor jet was gathering information relating to the test.

The preparations at Lop Nur, China's main nuclear testing facility in western Xinjiang were allegedly photographed by US spy satellite technology two weeks ago.

China signed the Comprehensive Test Ban Treaty in 1996, but has yet to ratify it.

US intelligence officials claim China has a covert testing program that relies on small nuclear explosions.

They also claim Chinese agents brought special equipment that can mask nuclear explosions from Russia several years ago.

Some officials believe the tests may be aimed at showing China's growing nuclear power as the spy plane dispute continues.

Others say it is an indication that President Jiang Zemin, who is considered to be a moderate in favour of building good relations with the US, has little control of the military.

The EP-3E aircraft at the centre of the spy plane dispute collects large amounts of communications and other electric signals.

Its sensitive listening equipment is capable of detecting communications thousands of miles inland, including any from Lop Nur.