A UN human rights envoy has visited prominent political activists held at Burma's notorious Insein jail before departing the military-ruled nation.
Mr Pinheiro was refused access to some political detainees
Paulo Sergio Pinheiro said the detainees included Labour activist Su Su Nway, who was arrested on Tuesday.
His request to meet detained opposition leader Aung San Suu Kyi was refused.
Mr Pinheiro is investigating allegations of widespread abuse during the ruling junta's crackdown following September's anti-government protests.
His five-day mission was to determine the numbers detained or killed.
Speaking at a news conference at Rangoon's airport, Mr Pinheiro said he also held talks with journalist Win Tin, who has been held since 1989 and is now in his late 70s.
He said he was also permitted to meet members of the 88 Generation Students group, who have been active in non-violent anti-government protests in recent years.
But the UN envoy said he had failed to meet Ms Suu Kyi or leading activist Min Ko Naing, who has been in custody since mid-August. He did not given any details of the conversations.
The visit followed talks with the foreign and information ministers in the capital, Naypyidaw, where Mr Pinheiro reiterated a request for broader access.
"While thanking the authorities for the wide range of meetings with government officials, the special rapporteur renewed to the authorities his request to be given access to other non-government interlocutors," a UN statement said.
Mr Pinheiro is making his first visit to Burma since 2003. The junta allowed him to return in an apparent concession to the international community, which had been critical of the generals' handling of September's protests.
The military says 10 people died in the crackdown on demonstrators, but diplomats fear the toll was far higher.
Hundreds of people are thought to be in custody. However, the government says it has released most of the 3,000 activists who were initially detained.
There have also been reports of more arrests in recent days.
On Tuesday, Su Su Nway was detained as she handed out leaflets, and three more arrests were reported on Wednesday.
Diplomats are divided on whether the international pressure on Burma is working.
On Tuesday the UN's special envoy to Burma, Ibrahim Gambari, told the Security Council that his recent visit had achieved "positive outcomes".
He said he was hopeful that a process of genuine dialogue between the military and the pro-democracy movement would emerge.
But others were more sceptical.
US ambassador to the UN, Zalmay Khalilzad, said he did not believe that "a fundamental shift has occurred in the regime's attitude to embrace substantive reconciliation and transition to democracy".