The United Nations said Thursday that the bodies of at least 87 people were found in a mass grave in Sudan's West Darfur state.
A statement from the U.N. human rights office said the dead included members of the Masalit ethnic group and that the bodies were found outside the city of Geneina.
The statement said local people were forced to bury the bodies between June 20 and June 21.
The U.N. said there was credible evidence that Sudan's Rapid Support Forces paramilitary group was responsible.
U.N. High Commissioner for Human Rights Volker Turk called for a "prompt, thorough and independent investigation."
"I condemn in the strongest terms the killing of civilians and hors de combat individuals, and I am further appalled by the callous and disrespectful way the dead, along with their families and communities, were treated," Volk said in a statement.
Some information for this report came from The Associated Press, Agence France-Presse and Reuters.