Myanmar's military junta had announced it would free 7,012 prisoners to mark the 75th anniversary of the country gaining independence.
Among more than 7,000 prisoners granted amnesty by Myanmar's junta this week were about 300 political prisoners, the United Nations has said.
"It's about 300 who were political prisoners," spokesman Jeremy Laurence told reporters on Friday, citing "credible sources".
He said that so far, 195 of those cases had been verified.
Local monitoring group AAPP also said it understood 300 political prisoners had been released. It had identified 223 of them and was working to verify other cases.
"The release of political prisoners in Myanmar is not only a relief to those unfairly detained, but also their families," Laurence said.
While welcoming the amnesty, Laurence pointed out that "on the very day that these political prisoners were released, another 22 were detained".
"So the situation continues."
And many of the people being detained for opposing military rule, he said, "have been subjected to torture and ill-treatment".
"Such detentions are not only intended to silence the junta's critics, but are also designed to instil fear."
Nearly 17,000 people have been arrested since the military coup in February 2021, and over 13,000 remain in detention, Laurence said, adding that the UN rights chief Volker Turk was preparing a report about the situation in Myanmar.
"The pathway out of Myanmar's crisis is not by locking people up, it is by allowing them to freely, fully and effectively participate in political life," he said.
The military junta, which seized power nearly two years ago, announced on Wednesday it would free 7,012 prisoners to mark the 75th anniversary of Myanmar gaining independence.
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