The period of turmoil in the city was started by the abortive coup attempted by the northerner Prime Minister Hissène Habré against the southerner President Félix Malloum: while Malloum and the national army loyal to him were defeated, the intervention in the battle of other northern factions rival to that of Habré complicated the situation. A temporary truce was reached in 1979 through international mediation, establishing the warlord Goukouni Oueddei as head of a government of national unity with his rival Habré as Defense Minister. The intense rivalry between Goukouni and Habré caused the eruption of new clashes in the city in 1980; N’Djamena found itself divided into sectors controlled by the various warlords. The tug-of-war reached a conclusion after many months only when Goukouni asked for the intervention of the Libyans, whose tanks overwhelmed Habré's defenses in the capital.