A decade of civil war followed, as the Hutu formed militias in the refugee camps of northern Tanzania. An estimated 300,000 people were killed in clashes and reprisals against the local population, with 550,000 citizens (nine percent of the population) being displaced. After the assassination of Ntaryamira, the Hutu presidency and Tutsi military operated under a power-sharing political system until July 1996, when Tutsi Pierre Buyoya seized power in a military coup. Under international pressure, the warring factions negotiated a peace agreement in Arusha in 2000, which called for ethnically balanced military and government and democratic elections.