U.N. human rights envoy Paulo Sergio Pinheiro has visited Burma's notorious Insein Prison Thursday in an effort to talk with political detainees before wrapping up his first visit to the country in four years.
It was not immediately clear whether he was able to meet with any inmates.
Pinheiro was allowed to visit the same facility on Monday, but was only permitted to meet with prison officials. U.N. officials later said they have been assured that Pinheiro would be able to meet with political detainees.
Burma arrested several more activists this week while Pinheiro was in the country, openly challenging international calls for the release of prisoners and a halt to detentions.
On Wednesday, Pinheiro met with the top U.N. diplomat in Burma, Charles Petrie, as well as more than 20 members of the diplomatic corps.
Petrie said the special envoy was "disturbed" by this week's arrest of a prominent labor activist, Su Su Nway, whose whereabouts are unknown.
Burma's military government crushed pro-democracy protests in September. Pinheiro is in the country to investigate how many people were killed or jailed during the crackdown.
According to Burmese officials, 10 people were killed and nearly three-thousand detained in the September crackdown. Diplomats and human rights groups say the true figures are much higher.