YANGON , Myanmar -LRB- CNN -RRB- -- Opposition leader Aung San Suu Kyi took the stand for the first time Tuesday and told a Myanmar court that she did not violate her house arrest when she offered temporary shelter to an American man who swam to her lakeside home . People of Myanmar living in Japan protest for the release of Aung San Suu Kyi on May 24 , 2009 in Tokyo , Japan . `` She was very confident , very firm , very clear , '' said Mark Canning , the British ambassador to Myanmar , who was among diplomats and journalists allowed to watch the proceedings . `` In a strange way , she commanded the courtroom , '' he said . Suu Kyi , who is being tried on subversion charges , said she did not learn immediately that John William Yettaw swam nearly two miles and snuck into her crumbling , colonial-era bungalow on May 3 . She was told about the visitor the next day by one of two housekeepers who are her sole companions in the heavily guarded residence , where she was under house arrest . Suu Kyi 's two helpers are also on trial , as is Yettaw . `` I did n't know , '' she said . `` I was upstairs . '' Under questioning by a judge for half an hour , Suu Kyi said she provided Yettaw food but allowed him only to `` stay temporarily . '' Yettaw left late May 5 , she said . `` He walked to the lakeside . But I do n't know which way he went , because it was very dark , '' Suu Kyi said . The Nobel Peace Prize laureate also acknowledged that Yettaw , a 53-year-old former military serviceman from Falcon , Missouri , had visited her once before last November . `` Did you report to the authority about his arrival ? '' the judge asked . `` No , '' she replied . Suu Kyi had earlier told supporters that she did not tell authorities about the latest intrusion because she did n't want Yettaw or anyone else to get in trouble . But it is this silence that the Myanmar 's military junta is trying her for . The government said Yettaw 's presence violated the conditions of Suu Kyi 's house arrest . The country 's regime rarely allows Suu Kyi any visitors , and foreigners are not allowed overnight stays in local households without government permission . Suu Kyi has been under house arrest for 13 of the past 19 years -- a confinement the military junta has regularly extended . Watch the U.N. secretary general explain what he is doing for Suu Kyi '' Her latest round of home detention -- after five years of confinement -- expires Wednesday , according to her supporters at home and abroad . Last week , the military began prosecuting Suu Kyi on allegations of subversion at a prison compound near Yangon . Her supporters say the move is meant to keep her confined even longer -- beyond the general elections that the junta has scheduled for next year . If convicted , Suu Kyi , 63 , could be sentenced to three to five years in prison . Before the proceedings got under way at the Insean Prison compound Tuesday , the junta said Suu Kyi 's house arrest did not expire for six more months . And though the government said it considered releasing her at the end of the term , it said it had no choice but to try her after she met with Yettaw . `` As Aung San Suu Kyi is the daughter of Gen. Aung San , the leader of our country , we were deeply thinking whether to extend her detention or not , '' Police Brigadier General Myint Thein told reporters Tuesday . `` Unfortunately , a U.S. citizen entered her house for two days . She allowed and made conversation with him , gave him food . `` These kind of actions broke the law , '' he added . `` This is why we have no way but to open a case . And we are very sad about this case . '' Gen. Aung San played an instrumental role in bringing about the country 's independence from British colonial rule . He was assassinated in 1947 and is still revered in Myanmar . Suu Kyi 's lawyers rejected the junta 's explanation , saying the United Nations had already deemed the opposition leader 's continuing detention unlawful under Myanmar 's state protection laws . `` The U.N. has said her house arrest expired a year ago , '' said Jared Genser , her U.S.-based lawyer . `` They are out of time , and they can not detain her any longer under their own law . '' Thein told reporters that the pro-democracy advocate had actually been under house arrest for four-and-a-half years . The official said Suu Kyi 's house arrest officially went into effect on November 28 , 2004 . That gives the government six more months to restrict her movement , he said . Genser countered the government 's account , citing the conclusion of the U.N. Human Rights Council . The law is unclear whether detention begins from the time a person is arrested or when a detention order is issued , the council said . `` This would suggest an interpretation that you start counting from the day you begin to detain her , '' Genser said . In Suu Kyi 's case , she was put under house arrest in May 2003 . `` You ca n't issue an order months later and use that as your starting point . That creates an unfair period of detention , '' he said . After Suu Kyi 's testimony Tuesday , the court asked the diplomats and journalists to leave . It denied a defense request to consult with Suu Kyi privately . The court then questioned Yettaw . He is charged with violating immigration laws and trespassing . The charges carry a maximum sentence of five years in prison . A lawyer selected by the U.S. Embassy is representing him . According to Yettaw 's testimony in court Friday , he made the unauthorized trip because he had a vision that Suu Kyi would be assassinated and he wanted to warn her . He muttered to himself during the proceedings , including utterances that Suu Kyi is innocent , said Nyan Win , spokesman for Suu Kyi 's National League for Democracy . Suu Kyi 's prosecution has prompted international criticism , with nine Nobel laureates -- including Archbishop Desmond Tutu of South Africa -- calling it a `` mockery . '' U.S. Secretary of State Hillary Clinton called the charges against Suu Kyi `` baseless '' and accused the junta of `` continuing resistance to a free and open electoral process . '' The Nobel laureate has been the face of Myanmar 's pro-democracy movement and the focus of a global campaign to free her . Her party won over 80 percent of the legislative seats in 1990 . But she was disqualified from serving because of her house arrest , and the military junta ignored the results . The government has said next year 's scheduled elections will reintroduce democracy in Myanmar . But its plan includes a clause that forbids citizens who bore children with foreigners from running for office . That makes Suu Kyi ineligible . She married a British man and has two sons with him . CNN 's Kocha Olarn in Bangkok , Thailand , and Saeed Ahmed contributed to this report .