YANGON: Myanmar democracy icon Aung San Suu Kyi was driven from her house to prison Thursday to face charges over a US man who swam across a lake and spent two days at her home last week, witnesses said. A convoy containing her car and several police vehicles swept out of the 63-year-old's lakeside residence in the main city of Yangon just after 7:00 am (0030 GMT), they said. Heavy security was in place and police sealed off the road to the house. Witnesses said about 15 minutes later Aung San Suu Kyi's car entered the notorious Insein prison on the outskirts of Yangon, where she is due to appear in court in connection with the incident involving the American. Her party earlier said she was expected in court at 10:00 am. US national John Yettaw was detained by police in the military-ruled nation last week for gaining uninvited access to the Nobel Laureate's house. A US diplomat saw him on Wednesday for the first time since his arrest. Nyan Win, a spokesman for Aung San Suu Kyi's National League for Democracy (NLD), told AFP: "Her lawyer said the authorities will charge the lady and her two maids at the court in Insein prison". "We still don't know what kind of charges they will be, but we will defend the facts," he said. Aung San Suu Kyi has spent most of the past 19 years detained in virtual isolation in her crumbling compound since the junta refused to recognise the NLD's landslide victory in the country's last elections in 1990. Her party said at the weekend that she was in poor health and called for her to be given urgent medical assistance after her doctor was arrested for questioning over the incident with the American. Lawyer Kyi Win said last week that Yettaw was an "adventurous" American acting of his own accord. Her latest period of detention at her home -- where she lives with her maids and is permitted occasional visits from her lawyer and doctor -- expires at the end of May but diplomats say it is likely the government will extend this sentence. Refering to the incident involving Yettaw, the state-run New Light of Myanmar newspaper, has said that the US citizen had confessed to arriving in Yangon on a tourist visa on May 2. He then swam to the compound the following night "and secretly entered the house and stayed there." Myanmar official sources said the man had succeeded in meeting Aung San Suu Kyi during his time at the house before he was arrested in the early hours of May 6 while swimming back across the lake. The newspaper said authorities confiscated his passport and a black haversack, torch, folding pliers, a camera, two US 100-dollar bills and some Myanmar currency notes.