Rwanda and the U.N.

In 1994, Rwandan armed forces killed 10 Belgian peacekeeping officers in a successful effort to discourage international intervention. It had started a day earlier.

On April 6, 1994, President Habyarimana of Rwanda was killed when his plane was shot down. It is not known if the attack was carried out by the Rwandan Patriotic Front (RPF), a Tutsi military organization stationed outside the country at the time, or by Hutu extremists trying to instigate a mass killing. In any event, Hutu extremists in the military, led by Colonel Theoneste Bagosora, immediately went into action, murdering Tutsis and moderate Hutus within hours of the crash. The Prime Minister ran with her family to the U.N. compound minutes after the plane was shot down and the Hutu military walked right in to the camp--with the U.N. troops watching--and murdered her in the open square.
The Belgian peacekeepers were then tortured and hacked to death with machetes, a key factor in the withdrawal of U.N. forces from Rwanda.

In approximately three months, the Hutu who controlled Rwanda brutally murdered an estimated 500,000 to 1 million innocent civilian Tutsis and moderate Hutus in the worst episode of ethnic genocide since World War II.
Interestingly, the two ethnic groups were very similar, sharing the same language and culture for centuries. A  law, however, required registration based on ethnicity.

75 percent of the Tutsis living in Rwanda were murdered.