Their story will ring alarm bells across Asia. 'The evidence is preliminary and needs to be verified, but this is something that would completely change the regional security status quo,' said Thitinan Pongsudhirak, the head of Thailand's Institute of Security and International Studies, Saturday.

'It would move Myanmar from not just being a pariah state, but a rogue state - that is, one that jeopardises the security and well being of its immediate neighbours.'

Washington is increasingly concerned that Myanmar is the main nuclear proliferation threat from North Korea, after Israel destroyed in September 2007 a reactor the North Koreans were apparently building in Syria.

Professor Ball said another Moscow-trained Myanmarese Army defector was picked up by US intelligence agencies early last year. Some weeks later, Myanmar protested to Thailand about overflights by unmanned surveillance drones that were apparently launched across Thai territory by US agencies. These would have yielded low-level photographs and air samples, in addition to satellite imagery.