The head of the United Nations' food-assistance agency has urged the international community to step up its support for the relief operation for Rohingya refugees in Bangladesh or risk "a massive catastrophic disaster."

David Beasley, head of the U.N.'s World Food Programme, said Sunday that the WFP needs $75 million in the next five to six months to meet current and anticipated food needs.

More than half a million Rohingya Muslims have fled into Bangladesh in little more than a month to escape a Myanmar military operation that has been condemned as ethnic cleansing. The crackdown was in response to a series of deadly attacks on security posts by Muslim insurgents.