The majority of the prisoners released were from the ethnic Kachin Independence Army, The Wall Street Journal reported. Others were from the Shan State Army and the Restoration Council of Shan State.
The move came as three-day peace talks between the Myanmar government and the Kachin Independence Organization in Myitkyina began Tuesday, the newspaper said. U.N. special envoy to Myanmar Vijay Nambiar was in attendance for the talks.
"Releasing these prisoners will help the national ceasefire process be more effective and set the talks on a positive tone," said Myint Win Maung, a representative of the League of Political Prisoners.
An estimated 100 political prisoners are still in detention in Myanmar, formerly known as Burma, the League of Political Prisoners said.
"We hope they will be released soon, since the government promised they will be freed by the end of the year," Maung said.