Burmese pro-democracy leader Aung San Suu Kyi is to face trial for breaching the conditions of her detention under house arrest, her lawyer has said.
Ms Suu Kyi will stand trial on 18 May, the lawyer, Hla Myo Myint, said, BBC reported.
She was taken to a prison from her home in Rangoon, where she has spent most of the past 19 years, to hear the charges.
A US man whose apparently uninvited visit to her home led to the charges, will also be tried on immigration and security offences, the lawyer added.
The American man, John Yettaw, was arrested after swimming across a lake to her house and staying there secretly for two days.
The charges are yet to be confirmed by the government.
But it looks as though this is a pretext to keep her detained until elections due in 2010 which the generals think will give them some legitimacy, says BBC South-East Asia correspondent Jonathan Head.
Another of her lawyers said they would contest the charge.
"The charge is going to be violating the conditions of her house arrest and what her lawyer is going to argue is that of course that's ridiculous because, yes under the terms of her arrest she cannot invite people to visit her but she of course did not invite this person to visit her," Jared Genser told the BBC.
"If somebody shows up at her doorstep in violation of Burmese law she cannot be held responsible for it."
Meanwhile EU special envoy Piero Fassino said there was "no justification" for the detention, AFP news agency reported.
A spokesman for her National League for Democracy (NLD), Nyan Win said he had been informed of the plan to try Ms Suu Kyi and two women who live with her by her lawyer, who visited Ms Suu Kyi in her off-limits house on Wednesday.
She was driven in a police convoy with the two aides from her house to the prison, eyewitnesses said.
Reports say she was charged under the country's Law Safeguarding the State from the Dangers of Subversive Elements, which carried a three-to-five-year jail term.
Ms Suu Kyi's main lawyer, Kyi Win, blamed Mr Yettaw for her detention, calling him a "fool".
The Burmese authorities have described the American as a 53-year-old Vietnam war veteran and resident of the state of Missouri.
Reports say security has been stepped up at the Insein jail, already a top security prison where a number of leading dissidents are incarcerated.
The Nobel Peace laureate has been under house arrest for much of the past 19 years.
The latest detention began in May 2003, after clashes between opposition activists and supporters of Burma's (Myanmar) military government.
The house arrest was extended last year - a move which analysts say is illegal even under the junta's own legal limits.
It is now due to expire at the end of May.
Earlier this month, the government rejected an appeal for the 63-year-old to be freed, despite NLD claims that she was suffering from low blood pressure and dehydration.
Her condition is said to have improved following a doctor's visit this week and Kyi Win said she had told him her health was good and she was in good spirits.
Ms Suu Kyi was detained after the NLD's victory in a general election in 1990. Burma's junta refused to allow the party to assume power.
The military are planning to stage an election next year which they hope will give their rule a veneer of legitimacy, our correspondent says.