South Sudanese President Salva Kiir and his bitter rival and former vice president Riek Machar, now leader of the SPLM-IO rebels, met in the Sudanese capital Khartoum to sign a "permanent" ceasefire agreement, pledging to form an inclusive transitional government. The parties agreed to open humanitarian corridors, release detainees, withdraw troops and militarily disengage. The transitional government is to form a national army and security forces not linked to tribalism. However, the challenges for the 36-month transition period are great. Millions in South Sudan are on the brink of famine, and more than 2.5 million have fled the country. Hundreds of thousands more—mostly members of minority ethnic groups—are internally displaced, with many sheltering in camps administered by the United Nations. Previous efforts at a negotiated peace have broken down. (Photo: Sudan Tribune)