More than 100,000 people have fled Sudan since heavy fighting broke out between rival forces on 15 April.
Officials warned of an “all-out catastrophe” if fighting does not end.
A further 334,000 people have been displaced within Sudan.
Fighting is continuing in the capital, Khartoum, between the army and the paramilitary Rapid Support Forces (RSF), despite a ceasefire due to be in force.
On Monday, the UN special envoy to Sudan, Volker Perthes said the two sides had agreed to enter into talks to negotiate a “stable and reliable” ceasefire.
Saudi Arabia was a potential venue for the talks.
