Myanmar President Thein Sein, speaking in London last week, said all "prisoners of conscience" held in the country's jails would be released by the end of the year as the country transitions into democracy, The Wall Street Journal reported.
The Assistance Association for Political Prisoners in Myanmar applauded the releases, but said the government still needed to do more.
"If the president wants national reconciliation, he has to release all other prisoners immediately and stop arresting anyone else," said Bo Kyi, the group's joint secretary.
Despite the release, some 80 political prisoners remain locked up, the association said. More than 70 others are facing trial.
Myanmar has freed thousands of political prisoners in the past two years. Human rights groups said whistleblowers who were former government workers are being held as political prisoners and should also be granted amnesty.