A UN envoy visited Myanmar's western border Tuesday as part of a human rights inspection ahead of national polls, as campaigners denounced the junta's treatment of ethnic groups in the area.

The trip to the region on the border with Bangladesh is part of a five-day mission to assess the military regime's progress on rights ahead of elections promised this year, the first in Myanmar for two decades.
Tomas Ojea Quintana left Yangon for Sittwe in Rakhine state on the state-run airline and was due to meet officials and non-governmental organisations before travelling by boat on Wednesday to visit a border prison, officials said.
"Mr Quintana will visit Butheetaung prison tomorrow," a Myanmar official told AFP on condition of anonymity. The official said Quintana would meet border control authorities at the prison and have dinner with state police.
Quintana began his five-day trip on Monday, days after Myanmar authorities freed a key aide to democracy icon Aung San Suu Kyi but amid criticism of the government's election plans.
The Argentinean envoy met judges and opposition lawyers in the former capital Yangon on Monday but officials said there were no plans yet for him to meet either Suu Kyi or the head of the country Than Shwe.
Suu Kyi's party deputy, Tin Oo, 83, was freed from seven years in detention at the weekend, but that came two days after the regime jailed a US citizen activist.
On his release Tin Oo immediately called for more than 2,100 other political prisoners to be freed.
Nobel Peace laureate Suu Kyi remains under house arrest and has said it is too early for her National League for Democracy (NLD) to decide if it will take part in polls that critics deride as a sham.
Suu Kyi's house arrest was extended last August by 18 months when she was convicted over an incident in which a US man swam to her lakeside house, effectively ruling her out of the polls and sparking global outrage.
Quintana, making his third trip to Myanmar since his appointment in 2008, is due to return to Yangon on Thursday to visit the notorious Insein prison, where many dissidents are held, and will later meet ethnic representatives.
On Friday he will go to the remote capital Naypyidaw to meet the home affairs minister, foreign minister, chief justice, chief attorney general, police chief and human rights officials before leaving Myanmar, according to an official.