A UN investigation has found that at least 131 people were killed at the end of November in the eastern Democratic Republic of Congo at the hands of the M23 rebel group.
It says investigations have confirmed the deaths of the civilians in two villages - Kishishe and Bambo - in the Rutsuhuru district of North Kivu province.
The UN says the victims were executed in what appears to be a reprisal to the current government offensive.
"This violence was carried out as part of a campaign of murders, rapes, kidnappings and looting against two villages in the Rutshuru territory as reprisals for the clashes between the M23" and other groups, it says.
The M23 rebels, who have captured several towns near the borders of Rwanda and Uganda this year, have denied they are attacking civilians.