Western governments have condemned new charges brought against Myanmar pro-democracy opposition leader Aung San Suu Kyi.
Ms Suu Kyi, 63, is detained in prison and is facing trial on Monday for breaching the terms of her house arrest after an apparently uninvited visit by American citizen John William Yettaw.
According to state media, Mr Yettaw claimed to have swum across Inya Lake and spent two days in Ms Suu Kyi's compound earlier this month. Ms Suu Kyi faces up to five years' jail for allowing him to stay.
US Secretary of State Hillary Clinton has demanded Ms Suu Kyi's immediate release, saying she is "deeply troubled" by the "baseless" charges against her.
Other world leaders also expressed concern over the detention, including New Zealand's Foreign Affairs Minister Murray McCully.
Mr McCully said the only thing Ms Suu Kyi is guilty of is standing up for the rights of the people of Myanmar in the face of appalling repression. He said her imprisonment is unacceptable and throws more doubt over the credibility of elections planned for next year.
United Nations Secretary-General Ban Ki-moon expressed "grave concern", and called on the government not to undermine Myanmar's national reconciliation process, his spokeswoman said.
Ms Su Kyi's party, the National League for Democracy (NLD), which won a landslide election victory in 1990 only to be denied power by the military, "strongly condemned" the charges, which come two weeks before her latest detention was due to expire.
British Prime Minister Gordon Brown earlier said he was "deeply disturbed" by the charges and he accused the Myanmar military government of seeking "any pretext, no matter how tenuous" to extend the detention.
The European Union special envoy to Myanmar, Piero Fassino, said there was "no justification" for the detention.
Thailand's prime minister also expressed concern on behalf of the Association of South East Asian Nations, one of the few groups that allow Myanmar as a member.
Ms Suu Kyi, a Nobel Peace laureate, has spent 13 of the past 19 years under some form of detention, with her latest spell starting in May 2003.
UN legal experts have said Ms Suu Kyi's continued house arrest was illegal under Myanmar law, which permits detention for five consecutive years before the accused must be freed or put on trial.
Ms Suu Kyi launched a legal appeal after her detention was extended last year in an apparent violation of the law. The junta said it could hold her for a sixth year and denied the appeal.
