In 1990, the Rwandan Patriotic Front (RPF), a rebel group composed of nearly 500,000 Tutsi refugees, invaded northern Rwanda from their base in Uganda, initiating the Rwandan Civil War. The group condemned the Hutu-dominated government for failing to democratize and confront the problems facing these refugees. Neither side was able to gain a decisive advantage in the war, but by 1992 it had weakened Habyarimana's authority; mass demonstrations forced him into a coalition with the domestic opposition and eventually to sign the 1993 Arusha Accords with the RPF. The cease-fire ended on 6 April 1994 when Habyarimana's plane was shot down near Kigali Airport, killing him. The shooting down of the plane served as the catalyst for the Rwandan genocide, which began within a few hours. Over the course of approximately 100 days, between 500,000 and 1,000,000 Tutsi and politically moderate Hutu were killed in well-planned attacks on the orders of the interim government. Many Twa were also killed, despite not being directly targeted.