Decrying what he calls the humanitarian "nightmare" for the refugees, Antonio Guterres is urging Myanmar to allow aid agencies into conflict-wracked Rakhine state.
Since an outbreak of violence in northern Rakhine state, Rohingya Muslims and others have been pouring into Bangladesh by the hundreds of thousands.
Speaking at the United Nations' first public meeting on the crisis, Secretary-General Antonio Guterres says the number of refugees has now topped half a million.
