YANGON: The trial of democracy icon Aung San Suu Kyi resumed Monday as Myanmar lashed out against Thailand — one of its few supporters in an international community likely to halt recent moves to improve relations with the country's military rulers.

Suu Kyi, due to testify this week, is widely expected to be found guilty for allegedly harbouring an American who swam across a lake to her residence. She faces up to five years in prison.

A list of four or five defense witnesses will be submitted to the court and statements from remaining prosecution witnesses are to be heard at Monday's session inside Yangon's security-ringed Insein prison, said Nyan Win, a spokesman for Suu Kyi's political party.

Already bombarded by criticism from Western nations, the junta turned on neighbouring Thailand, a partner in the 10-nation Association of Southeast Nation, or ASEAN, accusing its neighbour of violating the bloc's principle by interfering in Myanmar's internal affairs.

Thailand, the grouping's current chairman, last week expressed "grave concern" over the trial, saying "the honour and the credibility of the (Myanmar government) are at stake."

A statement from Myanmar issued Monday responded: "It is sadly noted that (Thailand) failed to preserve the dignity of ASEAN, the dignity of Myanmar and the dignity of Thailand."

Suu Kyi, who has been in detention without trial for more than 13 of the past 19 years, is being tried on charges of violating the terms of her house arrest after the uninvited American, John W. Yettaw, swam to her home earlier this month and stayed for two days. Suu Kyi pleaded not guilty Friday.

But Myanmar's courts operate under the influence of the ruling military, and almost always deal harshly with political dissidents.

The charges against her are widely seen as a pretext for the government to keep her detained during polls it has scheduled for next year as the culmination of its "roadmap to democracy," which has been criticised as a fig leaf for continued military rule. She was due to have been released from her latest term of house arrest this Wednesday.

The trial comes weeks after the European Union announced it was stepping up humanitarian aid to the impoverished country, also known as Burma, and the United States said it was reviewing its policy — including speculation that it might soften sanctions the regime says have crippled its economy.

But now the European Union is talking of introducing tougher sanctions in response to the trial and the administration of President Barack Obama has announced it will continue its economic penalties. Obama extended a state of emergency against the country after Suu Kyi's arrest. Sanctions would have expired had the emergency order not been extended.

EU External Relations Commissioner Benita Ferrero-Waldner, in Bangkok on her way to the ASEAN-EU foreign ministers meeting in Hanoi, Monday called on China and India to push for democratic change in Myanmar and welcomed ASEAN's unprecedented criticism of Myanmar.

"This was a remarkable statement. At the moment when we all hoped to see Aung San Suu Kyi released she is imprisoned again. That was of course a big negative surprise to the international community," she told reporters.

Sean Turnell, a Myanmar expert at Australia's Macquarie University, said the timing of the trial shows the junta "never misses an opportunity to miss an opportunity."

"I think there was, prior to these latest events, a strong likelihood that the U.S. and Europe positions on Burma may have softened, and that some sanctions may even have been on the table" for review, Turnell said in an e-mail interview. "The regime have now shot themselves in the foot so to speak — and anything like this would seem to be decidedly off the table now."

David Steinberg, a Myanmar specialist at Georgetown University in Washington, said there had been talk of "small steps toward easing relations" within the Obama administration. But he said a guilty verdict makes increased engagement with the ruling generals unlikely for now.

"I think they wanted to make some overtures, but this will make it far more difficult," Steinberg said of the Obama administration. "The junta needed to respond significantly as well at each step, and this would set it back."

Donors may also be less willing to fund a three-year, $700 million rebuilding plan for the Irrawaddy delta, which was devastated by a cyclone last year that killed more than 138,000 people.

No one expects a guilty verdict to spark an uprising in Myanmar against the junta after its bloody suppression of pro-democracy demonstrations in 2007, which killed at least 31 people. Hundreds more activists were sentenced to lengthy prison sentences.