The UN special envoy to Myanmar met with junta leaders Saturday as he paves the way for a visit by Secretary General Ban Ki-moon next month expected to focus on the trial of Aung San Suu Kyi.
Nigerian diplomat Ibrahim Gambari was expected to meet Foreign Minister Nyan Win in the junta's remote administrative capital Naypyidaw before returning to the main city Yangon to round off his low-key visit.
Myanmar officials said no meetings with more senior military leaders could be confirmed, nor were there any immediate plans for Gambari to see Nobel laureate Aung San Suu Kyi, members of her party or international diplomats.
The UN troubleshooter arrived in the country for talks with the military regime on Friday and is due to brief UN chief Ban on the outcome of his two-day mission.
Ban will then decide whether to go ahead with plans to visit Myanmar early next month, according to UN sources in New York.
The UN boss and Gambari have been trying to persuade Myanmar's ruling generals to free all political detainees, including Aung San Suu Kyi, and to steer their country on the path to democracy and national reconciliation.
Aung San Suu Kyi, 64, is being held in jail on charges of violating her house arrest after an American man, John Yettaw, swam to her lakeside house earlier this year. She risks up to five years in prison if convicted.
She has spent 13 of the past 19 years in detention since the ruling generals refused to recognise the landslide victory of her National League for Democracy party (NLD) in 1990 elections.
Critics accuse the junta of trying to keep her locked up ahead of elections promised in 2010.
Gambari was named the top UN envoy for Myanmar in 2006 but his previous visits have produced few results.
Aung San Suu Kyi refused to meet him in August 2008, apparently after he failed to secure reform pledges from the regime.
The charges against Aung San Suu Kyi come amid a wide-ranging crackdown on the opposition that has been carried out since the ruling generals crushed protests led by Buddhist monks in 2007.
More than 2,100 political prisoners remain imprisoned, according to United Nations figures.
Yettaw, a devout Mormon and US military veteran, has told the trial that he swam to Aung San Suu Kyi's home because he was on a mission from God to warn her about a "vision" that she would be assassinated.
The junta appeared to toughen its stance on the eve of Gambari's visit when the national police chief held a press conference to show alleged links between Yettaw and exiled dissident groups based in Thailand.
The case has drawn widespread international condemnation, with US President Barack Obama describing it as a "show trial" and some of Myanmar's neighbours breaking their usual silence on the issue.
The United States and Europe have both imposed sanctions against Myanmar, formerly known as Burma, which has been ruled by the military since 1962.