The announcement comes as the country formerly known as Burma is working to meet Myanmar President Thein Sein's deadline for releasing all political prisoners by the end of 2013, the Los Angeles Times reported.
Since coming to power in 2011, Thein Sein has freed more than 2,000 political prisoners
Thein Sein's office said in a statement Friday that the amnesty was granted to "respect humanitarian grounds" and allow those freed to "assist in national building."
Meanwhile, the Thailand-based Assistance Association for Political Prisoners in Myanmar, a watchdog group, said about 60 political prisoners remain in various prisons across Myanmar, while another 255 face charges for political activities.
"We want the unconditional release of all prisoners at the earliest," said Bo Kyi, joint secretary of the group. "It is difficult to say that there will not be any more arrests."
Analysts say the timing of the prisoner releases coincided with Myanmar hosting several high-profile foreign visitors. Former U.S. President Clinton is in Myanmar for his foundation, and former British Prime Minister Tony Blair is also visiting the country.
"This is routine practice of the president to release prisoners [around the time of a] a big international event," said Tint Swe, chairman of the Burma Center Delhi. "If the government genuinely had good intentions and their mind was made up to release political prisoners, just release them anytime."
"The regime really needs to take some image-saving measures apart from the time-to-time release of political prisoners, to prove that they are serious and looking for proper reforms," said Tint Swe.