YANGON, Myanmar -- Myanmar freed five prisoners Tuesday and more are expected to be released next week as part of a pledge by the country's president to free all political prisoners by the end of 2013.

They were freed after President Thein Sein granted a pardon Monday to those convicted of or charged with a variety of political offences, such as unlawful association, high treasons, contempt of government and violations of the peaceful assembly law.

The amnesty follows a promise by Thein Sein in July that all political prisoners will be freed by the end of the year. In addition, the decree halted all ongoing trials and investigations connected with those charges.

Those freed had their names on list from the Political Prisoners Scrutinizing Committee, said Bo Kyi, a member of the committee. He added that "more people are expected to be freed in the next batch in the first week of January."

"We welcome the presidential pardon order. However, several steps need to be taken to maintain a level of zero political prisoners. There must be rule of law and more political freedom to maintain that level," Bo Kyi said.

The five were freed from district prisons and Yangon's notorious Insein prison.

"We were freed today because the laws that were used to put us behind bars are weak. Anyway, I respect the president for keeping his promise to free political prisoners before end of the year," said Yan Naing Tun, one of several political prisoners freed from Insein prison.

Yan Naing Tun and Aung Min Naing, who led a march to the headquarters of the ethnic Kachin Independence Organization in northern Myanmar early this year, were serving seven-month sentences for breaking the Peaceful Assembly Law because they had not gotten permission for their march.

Ye Aung, a former political prisoner and member of the prisoner scrutinizing committee, said another 200 activists facing trial for political charges will immediately have those charges dropped.

The pardon may not cover all prisoners listed by the committee as political detainees as some were also convicted of other crimes, such as murder, he said.

Since Thein Sein became president, he has freed about 1,300 political prisoners, Ye Aung said.

The office of the U.N. High Commissioner for Human Rights welcomed the pardons but lamented that they did not include three workers of international non-governmental organizations detained in since 2012, or two human rights defenders in Rakhne state, Dr. Tun Aung and U Kyaw Hla Aung.

According to Amnesty International, Tun Aung was arrested as an agitator in June 2012, a week after trying to help quiet a crowd in Rakhine, where violence had broken out between Buddhists and the minority Rohingya Muslim community. U Kyaw Hla Aung, a Rohingya lawyer, has been detained since July 2013, according to U.N. Amnesty says he has long been the target of harassment and that before his latest arrest, had already spent 16 years in prison "due to his involvement in peaceful activities."

"We ask the authorities to release those prisoners and to ensure that the prisoner review committee continue its work to resolve all pending cases," said Cecile Pouilly, a spokesperson for the high commissioner.

Thein Sein, a former general who was elected president in 2011 after five decades of repressive military rule, instituted political and financial reforms to lift the country's sagging economy. Myanmar had faced sanctions from Western nations -- now mostly lifted -- because of its poor human rights record and undemocratic rule.

The release of political detainees has been a benchmark used by Western nations to judge Thein Sein's administration, with previous releases triggering decisions by some nations to ease sanctions.

Ye Aung said that during Thein Sein's administration many activists had been charged under a section of the Peaceful Assembly Law that carries a maximum one-year prison term for those who stage protests without official permission.

Associated Press writer Alexandra Olson at the United Nations contributed to this story.