More than 1,000 people may already have been killed in Myanmar's Rakhine state, mostly members of the Muslim Rohingya minority, a senior United Nations representative told AFP on Friday -- twice the government's figure.

"Perhaps about a thousand or more are already dead," said Yanghee Lee, the UN special rapporteur on human rights in Myanmar. "This might be from both sides but it would be heavily concentrated on the Rohingya population."