At least 87 people including ethnic Masalits were buried in a mass grave in Sudan's West Darfur, the UN human rights office said on Thursday, saying it had credible information that the Rapid Support Forces were responsible.
"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," said UN High Commissioner for Human Rights Volker Turk in a statement.
He called for a prompt and thorough investigation.
The raging conflict in Sudan has driven more than 3 million people from their homes, including over 700,000 who fled to neighboring countries, the UN said Wednesday.
Entire towns and villages have been burned to the ground and looted, especially in West Darfur province.
The clashes have killed more than 3,000 people and wounded more than 6,000 others, Health Minister Haitham Mohammed Ibrahim said in televised comments last month. The casualty tally is likely much higher, according to doctors and activists.