The pardon was announced on state television Tuesday amid renewed calls for President Thein Sein's government to release hundreds more political prisoners still believed to be behind bars.
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.
Ye Aung, a former prisoner and a member of the government committee, said at least 59 political prisoners were released Tuesday and that at least 300 others remain incarcerated, most of them members of ethnic minorities.
Opposition leaders and rights groups have accused the government of using political prisoners as "bargaining chips" — releasing some to prove progress, holding others to push the West to ease more sanctions.
The last major prisoner release coincided with a visit to the country by President Barack Obama. Tuesday's pardon came after the European Union dropped all political and economic sanctions against Myanmar to support the country's "remarkable process" in democratic reforms, while warning that it must control recent ethnic violence.
"Amnesties almost always coincide with international events. Today's amnesty coincides with the lifting of EU sanctions," said Ko Ko Gyi, who was released from jail last year and is one of the country's most prominent former political prisoners.
"The government should acknowledge the existence of political prisoners and release them all," he said.
One of those released Tuesday from Yangon's notorious Insein prison, Zaw Moe, said he was among at least five political prisoners freed there. But he said he could not be content because "many of my friends remain" behind bars. "I'm worried about them."
Zaw Moe had been sentenced to an 18-year term in 2008 for alleged links to dissident groups fighting against the former military government.
