A senior Myanmar official has spoken out against the country's opposition leader Aung San Suu Kyi, warning foreigners not to interfere in the case.
Major General Aye Myint, Myanmar's deputy defence minister, told a security forum in Singapore that Aung San Suu Kyi "covered up" the truth by failing to report an American man in her home.
He said this left no option but to open legal proceedings in accordance with the law.
Aung San Suu Kyi, a Nobel peace laureate, is facing up to five years' detention on charges relating to the surprise visit of an eccentric American to her lakeside prison home in early May.
John Yettaw, 53, who is a Mormon and US military veteran, was arrested on May 6 after swimming to Ms Suu Kyi's house using a pair of homemade flippers and spending two nights there.
He is also on trial.
Ms Suu Kyi has spent 13 of the past 19 years in detention.
In his speech on Sunday to regional security officials and experts, Myanmar's deputy defence minister said the case against Aung San Suu Kyi was an internal matter for Myanmar to resolve without foreign intervention.
"Countries should refrain from interfering in the internal affairs of Burma that will affect peace and security of the region," said Major General Aye Myint.
Critics say Myanmar's military regime trumped up the charges in a bid to keep her locked up ahead of elections in 2010, as the latest six-year period of her house arrest expired on Wednesday.