The US State Department expressed concern on Thursday after Myanmar's military junta detained and charged pro-democracy icon Aung San Suu Kyi with breaching the terms of her house arrest.
"We have seen this report, which is certainly troubling if true," State Department spokesman Ian Kelly said about Suu Kyi's expected trial on Monday to face the charges, which carry a maximum jail term of five years.
US Secretary of State Hillary Clinton "has seen it as well, and has asked the Department to work to get more information," added Kelly.
The charges would stretch the 63-year-old's detention past its supposed expiry date this month and through elections that are due in 2010.
US national John Yettaw was detained last week after swimming across a lake and hiding inside Suu Kyi's off-limits home for two days. He was also charged with violating the security law and immigration conditions, according to Hla Myo Myint, one of the democracy activist's lawyers.