Yangon - Myanmar's main opposition party on Wednesday called for the release of all political prisoners and their leader Aung San Suu Kyi, who has spent the past six years in detention and faces another three to five years in jail if found guilty of new charges.

Hundreds of National League for Democracy (NLD) members gathered at their party headquarters in Yangon to commemorate the 19th anniversary of their victory in the
1990 general election.

Although the NLD won more than 80 per cent of the contested seats in the 1990 polls, they have been blocked from assuming power by Myanmar's junta for the past 19 years.

Wednesday also marked the sixth anniversary of the arrest of NLD leader Aung San Suu Kyi on charges of threatening national security for campaigning in central Myanmar.

Suu Kyi's six-year term was not extended Wednesday but she remained in jail, nonetheless.

On May 8, Suu Kyi was transferred from her family home-cum-jail to Insein Prison, where a special court is trying her on charges of violating the terms of her detention by allowing US national John William Yettaw to swim to her lakeside compound on May 3. He swam away on May 6, and was arrested by police.

Suu Kyi could face a minimum of three and maximum of five years in jail if found guilty.

On Tuesday she testified for the first time before the court, which has been in session since May 11.

As part of her defence, Suu Kyi presented a two-page statement to the court, the contents of which were made available by the NLD on Wednesday.

The prosecution has accused Suu Kyi and her two household aides of allowing Yettaw, a 53-year-old member of the Mormon sect, to visit on a previous occasion on November 30, last year.

In her statement, Suu Kyi acknowledged Yettaw's previous visit but said she had informed authorities of it.

"I had reported this incident to authorities via Doctor Tin Myo Win who came to my house on 4 December 2008 for my medical check-up," Suu Kyi said in her statement.

"But, there were no enquiries, investigations or action by authorities after the reporting, and authorities did not warn us to report immediately for future incidents like that," she added.

On Tuesday, a judge asked Suu Kyi why she had not reported Yettaw's May 3-5 visit to authorities.

"I had planned to report this incident to Doctor Tin Myo WIn when he was scheduled to visit us on 7 May, but Doctor Tin Myo Win was not allowed to come on that day. Instead of him, police came to my house," Suu Kyi said in her statement.

For the past six years Suu Kyi was kept in near-complete isolation at her Yangon home, with only her two aides permitted to live with her. She was allowed regular visits by her family doctor Tin Myo Win and occasional visits by United Nations special envoys.

Suu Kyi's trial has been widely criticized by the international community and even some of Myanmar's close allies in the Association of South-East Asian Nations, who have raised concerns that the frail pro-democracy leader may face five more years of imprisonment, perhaps in Insein jail, which is notorious for harsh treatment of inmates.

US President Barack Obama on Tuesday urged Myanmar's military regime to "immediately and unconditionally" release Aung San Suu Kyi from detention.

Obama called the current court case against her a "show trial based on spurious charges."

The trial casts "serious doubt on the Burmese regime's willingness to be a responsible member of the international community. This is an important opportunity for the government in Burma to demonstrate that it respects its own laws and its own people, is ready to work with the National League for Democracy and other ethnic and opposition groups, and is prepared to move toward reconciliation," Obama said.(dpa)