24 years after the Rwandan genocide, 200 bodies were discovered east of the capital, Kigali.
Volunteers began to extract the bodies on Wednesday.
The alert was given by a woman who said she saw people burying bodies in 1994.
The Rwandan genocide took place between April and July 1994.
More than 800,000 people were killed in this genocide, considered the last genocide of the 20th century.
Many people have seen their entire families wiped out by death squads.