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,
Tutsi Since Burundi's independence, more extremist Tutsi came to power and oppressed the Hutus, especially those who were educated. Their actions led to the deaths of up to 200,000 Hutus. Overt discrimination from the colonial period was continued by different Rwandan and Burundian governments, including identity cards that distinguished Tutsi and Hutu. In 1993, Burundi's first democratically elected president, Melchior Ndadaye, a Hutu, was assassinated by Tutsi officers, as was the person entitled to succeed him under the constitution. This sparked a genocide in Burundi between Hutu political structures and the Tutsi military, in which "possibly as many as 25,000 Tutsi"