Myanmar's president pardoned 56 political prisoners Tuesday, an amnesty apparently timed to highlight the government's reforms ahead of a regional summit as well as important negotiations with a rebel group at home.

President Thein Sein ordered the prisoners' release just ahead of a forum in Brunei to be attended by leaders from across Southeast Asia and the Pacific. At the Association of Southeast Asian Nations summit, Myanmar is expected to face tough questions about ongoing sectarian violence that has targeted Muslims.

It has become a pattern for prisoner amnesties in Myanmar to coincide with high-profile international meetings as a way of highlighting the nominally civilian government's reforms since taking office after years of absolute military rule.

In July, Thein Sein pledged during an official visit to Britain to release all remaining political prisoners by the end of the year.

The release of political detainees has been a concern of the United States and other Western nations who are trying to promote Myanmar's transition to full democracy. However, new prisoners continue to be detained for political offenses.

A member of the government's political prisoner scrutiny committee, Ye Aung, said the released included members of several ethnic minorities.

Among them were more than a dozen ethnic Kachin, a move that intentionally coincided with peace talks being held Tuesday in Kachin state between government negotiators and the ethnic Kachin Independence Army, said an official who declined to be named, saying he was not authorized to speak to the media.

Myanmar for decades has faced rebellions from several ethnic groups seeking autonomy. The Kachin are the only major rebel group that has not reached a cease-fire agreement with Thein Sein's government, which came to power in 2011 after almost five decades of harsh military rule.

There have been 15 previous rounds of talks but no resolution is in sight, with the Kachin insisting on a comprehensive political settlement, not just a cease-fire.

Hundreds of prominent political detainees have been freed since Thein Sein, a former general, took office. According to Ye Aung, himself a former prisoner, more than 130 political prisoners are still believed to be jailed.

Before Tuesday's releases, his committee had identified 189 political prisoners still incarcerated, including 22 who were sentenced last month in Rakhine state under Section 18 of the peaceful assembly law for their failure to seek permission to stage peaceful protest.

Rakhine has been the main battleground for communal clashes between Buddhists and Muslims.

"The government is releasing political prisoners, but on the other hand more are being arrested under various laws including Section 18 of the peaceful assembly law," said Ye Aung. "The president has promised to free all political prisoners, but it is important that fresh arrests under various undemocratic laws should also be stopped."

Myanmar has routinely denied the existence of political prisoners, saying all people sentenced to jail have been convicted legitimately of breaking the nation's laws. Nevertheless, hundreds of prominent political detainees have been freed since the former general took office two years ago after a long-ruling army junta was dissolved.

In February, Thein Sein appointed a 16-member committee to review the cases of inmates identified by opposition groups as prisoners of conscience. Some cases are complicated because they involve bombings or threats to state security or national stability. Rights groups say many other people were wrongfully convicted and given extreme sentences for actions that would not be considered crimes elsewhere.