The Burmese government may be attempting to "expel" its Rohingya Muslim minority, the UN human rights investigator to the country has said.
Last month, the UN's human rights office said the campaign of killings and rapes probably amounted to crimes against humanity and ethnic cleaning.
After security crackdown caused international outcry, Burma may be using bureaucratic means to get rid of its Rohingya population, UN special rapporteur Yanghee Lee said.
She told the UN Human Rights Council the evidence "indicates the government may be trying to expel the Rohingya population from the country altogether."
Around 75,000 Rohingya have fled to Bangladesh after the Burmese military launched a crackdown in the north of Rakhine state after nine policemen were killed last October.
After visiting Burma twice in the last year, Ms Lee said she had heard "harrowing account after harrowing account."
She told the Council: "I heard allegation after allegation of horrific events like these, slitting of throats, indiscriminate shootings, setting alight houses with people tied up inside and throwing very young children into the fire, as well as gang rapes and other sexual violence."
She had been denied access to parts of Burma she hoped to visit, include Kachin state, another area of ethnic violence.
"I must confess that there were times that I had seriously questioned the nature of the cooperation," she said.
Burma's ambassador Htin Lynn called the allegations of crimes against humanity unverified and one-sided. He said security operations in Rakhine had stopped and the curfew was eased earlier this month.
"The situation in Rakhine state is very complicated in nature and thus requires complicated answers. It also requires greater understanding by the international community," he said.
Ms Lee said she is "disappointed" by the lack of "appetite" at the Human Rights Council to back her call for the creation of a Commission for Inquiry.
Key players, including the European Union, are yet to back Ms Lee's call over concern it may threaten the country's fragile move towards democracy.
"If these allegations are indeed exaggerated allegations, everyone needs to know," Ms Lee told The Associated Press.
"If these allegations are true, I think Myanmar needs to know because this will be the obstacle to them fully reforming and transforming into a fully democratic society."
