Hutu Rwanda, this led to the "Social revolution" and Hutu violence against Tutsis. Tens of thousands of Tutsis were killed and many others fled to neighboring countries, such as Burundi, Uganda and expanding the Banyamulenge Tutsi ethnic group in the South Kivu region of the Belgian Congo. Later, exiled Tutsis from Burundi invaded Rwanda, prompting Rwanda to close its border with Burundi. In Burundi, a campaign of genocide was conducted against Hutu population in 1972, and an estimated 100,000 Hutus died. In 1993, Burundi's first democratically elected president, Melchior Ndadaye, who was Hutu, was believed to be assassinated by Tutsi officers,
Rwandan genocide only one dominated by an opposition party. Opposing the genocide, Habyalimana was able to keep relative calm in the province, until he was deposed by the extremist Sylvain Ndikumana. Finding the population of Butare resistant to murdering their fellow citizens, the government flew in militia from Kigali by helicopter, and they readily killed the Tutsi. Most of the victims were killed in their own villages or in towns, often by their neighbors and fellow villagers. The militia typically murdered victims with machetes, although some army units used rifles. The Hutu gangs searched out victims hiding in churches and school buildings,