 Nimeiry, concerned by the warm welcome Gaddafi had given to al-Mahdi, his exiled opposition, began to encourage the fragile administration of Félix Malloum, the new Chadian president after Tombalbaye's 1975 assassination.In retaliation, Gaddafi sent a 1200-man force across the desert to assault Khartoum directly.The Libyan force was barely defeated after three days of house to house fighting and Nimeiry chose to support the most anti-Libyan of the various Chadian leaders, Hissène Habré, giving his Armed Forces of the North sanctuary in Darfur.