The head of the U.N. refugee agency said on Monday more international support was needed for hundreds of thousands of Rohingya refugees in Bangladesh, a day ahead of a donor conference aiming to raise $1 billion to fund the response, Reuters reported.

Close to a million Rohingya have been living in crowded camps in southern Bangladesh that comprise the world’s largest refugee settlement since fleeing a military crackdown in Myanmar's Rakhine state nearly four years ago.

Speaking to Reuters, Filippo Grandi said the fate of the Rohingya was at risk of being forgotten in the wake of a coup by the army in Myanmar that has thrown the country into further turmoil and sent more people fleeing to the borders.