UN chief Ban Ki-moon met the reclusive head of Burma's military junta on Friday for what he said would be "tough talks" aimed at securing the release of pro-democracy leader Aung San Suu Kyi.
Ban flew into Naypyidaw, the remote stronghold of Senior General Than Shwe and his regime, shortly after a prison court adjourned the widely condemned trial of the detained Nobel Peace laureate for another week.
"This is my second time in your country and I am very pleased to continue our discussions. I appreciate your commitment to move your country forward," Ban said in his opening statement to Than Shwe.
"I would like to contribute, to work together, for peace and prosperity," he added.
The UN secretary general earlier said he would urge Than Shwe for permission to visit the 64-year-old Aung San Suu Kyi, who was transferred from house arrest to Rangoon's notorious Insein prison in May.
She has spent most of the past two decades in detention and now faces five years imprisonment if convicted on charges of violating her house arrest after an American man swam uninvited to her lakeside house.
"It is a very tough mission," Ban told reporters shortly after arriving in Rangoon earlier Friday.
"One of my objectives is to obtain the release of all political prisoners including Aung San Suu Kyi," he said, adding that he would also "convey the concern of the international community" and press for reconciliation and democracy.
Rights groups warn that the trip will be a "huge failure" if he does not secure the release of Aung San Suu Kyi.
Critics have accused the junta of using the trial to keep her locked up for elections promised in 2010.
She appeared in court on Friday but the trial was adjourned for a week because the judges had not received an earlier judgement barring two defence witnesses, said Nyan Win, spokesman for her National League for Democracy (NLD).
"Daw Aung San Suu Kyi attended the trial this morning but the court said that as they haven't got the case from the Supreme Court the trial is suspended to July 10," Nyan Win said.
The case has sparked international outrage, with US President Barack Obama calling it a "show trial" and a host of world leaders and celebrities calling for her release.