GENEVA - The United Nations refugee agency (UNHCR) said on Friday that peace and stability must be restored in Myanmar's northern Rakhine state before any Rohingyas can return from Bangladesh, under international standards on voluntary repatriation.

"It is critical that the returns are not rushed or premature," UNHCR spokesman Adrian Edwards told a Geneva briefing. "People can't be moving back in into conditions in Rakhine state that simply aren't sustainable."

Some 20,000 Rohingya fled Myanmar to Bangladesh in November, and at least 270 so far in December, bringing the total since violence erupted on Aug. 25 to 646,000, according to UNHCR and Leonard Doyle of the International Organization of Migration (IOM).