UN Secretary-General Antonio Guterres has called for an immediate ceasefire in Sudan's brutal civil war, which the UN says has created the world's worst humanitarian crisis. Guterres's appeal, made late on Friday, follows a peace initiative presented by Sudan's Prime Minister Kamil Idris to the UN Security Council on Monday, which called for the paramilitary Rapid Support Forces (RSF) to disarm. The plan was rejected by the RSF as wishful thinking. The war erupted in April 2023 when a power struggle broke out between the Sudanese army and the RSF paramilitary group.