Democrat Senator Jim Webb, the chairman of the Senate Foreign Relations Committee's East Asia and Pacific Affairs Subcommittee, became the first senior US official to meet the reclusive Myanmar general in the capital Naypyidaw.
Webb later had a nearly hour-long meeting with Nobel peace laureate Suu Kyi at a government guesthouse near her home in Yangon, media reports said.
This was the pro-democracy leader's first meeting with a foreign dignitary since she was sentenced to 18 more months of house arrest earlier this week. The junta triggered global condemnation after a court convicted American John Yettaw and Suu Kyi over a May incident, in which he swam uninvited into her lakeside home.
Suu Kyi was charged with violating the terms of her house arrest. Webb succeeded in obtaining the release of Yettaw, his office in Washington said in a statement.
"Yettaw will be officially deported from Myanmar on Sunday morning. Senator Webb will bring him out of the country on a military aircraft that is returning to Bangkok on Sunday afternoon," it said.
The statement said Webb also appealed for the release of the pro-democracy leader, who has spent most of the last two decades under house arrest.
"Senator Jim Webb has finished up a two-day visit to Myanmar by obtaining the release of American prisoner John Yettaw and meeting with Nobel Peace Prize Laureate Aung San Suu Kyi," his office said.
"Webb, who on Saturday became the first American leader ever to meet with Myanmar president Than Shwe, raised both issues during his meeting. He also requested that the country's leadership release Suu Kyi from her 18-month sentence of house arrest, following her recent conviction for violating the terms of her house arrest," it said.
Webb said, "It is my hope that we can take advantage of these gestures as a way to begin laying a foundation of goodwill and confidence-building in the future."
Yettaw, a diabetic and epileptic former army veteran, had been lodged at Yangon's notorious Insein Prison.
Webb described the meeting with Suu Kyi as an opportunity "for me to convey my deep respect for the sacrifices she has made on behalf of democracy around the world".
The Senator's trip, made on a private capacity, comes soon after former US President Bill Clinton visited another reclusive nation North Korea and secured the release of two woman American scribes jailed there.
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