An overcrowded boat carrying Rohingya Muslims fleeing Myanmar has capsized in the confluence of a river and the Bay of Bengal and at least 12 people are dead.

Five of the dead were children, police said.

Up to 35 people were on the boat on Monday and eight survived the capsizing, local police official Mainuddin Khan said.

He said rescuers had retrieved 12 dead bodies but it was not exactly clear how many were missing. The search was continuing, but the sea remained rough.

The capsizing occurred near the Shah Porir Dwip in Bangladesh's southern coastal district of Cox's Bazar as the boat was moving toward Bangladesh late Sunday.

Hundreds of thousands of Rohingya have fled Myanmar since August 25 when the military launched a crackdown that had been decried by the United Nations as "ethnic cleansing."

Including Sunday's capsizing, boat accidents have killed at least 155 Rohingya trying to reach Bangladesh.

Myanmar's military launched what it described as "clearance o
perations" after an insurgent group attacked security posts and killed several police and border guards.

The UN said Myanmar's response was "disproportionate" compared to the insurgents' action.

The refugees arriving in Bangladesh have described indiscriminate violence and widespread arson in their home villages in Myanmar's Rakhine state along the Bangladesh border.

Bangladesh's Prime Minister Sheikh Hasina says her government will continue to support the Rohingya but Myanmar must take them back.