M23 rebels killed at least 131 civilians in eastern Democratic Republic of Congo on November 29-30 according to preliminary findings, the UN mission in the country said.

Authorities in Kinshasa had said that some 300 people, almost all civilians, had died in M23 attacks in the village of Kishishe in the eastern North Kivu province. The group had denied being behind the massacre, blaming "stray bullets" for the deaths of just eight civilians.

The victims were killed "as part of reprisals against the civilian population," the UN's MONUSCO mission said in an overnight statement, adding that 102 men, 17 women and 12 children were "arbitrarily executed" by bullets or other weapons.

"Eight people were wounded by bullets and 60 others kidnapped. At least 22 women and five girls were raped," it said.

"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 armed groups, the statement said.

The UN findings centred on the neighbouring villages of Kishishe and Bambo. Investigators could not go to the villages because of security concerns, but interviewed 52 victims and witnesses in the town of Rwindi 20 kilometres (12 miles) away

The mineral-rich east of DR Congo has been restive for years, with numerous militias operating in the area.

M23, a mostly Congolese Tutsi group, resumed fighting in late 2021 after lying dormant for years, claiming that the DRC had failed to honour a pledge to integrate its fighters into the army, among other grievances.

Its re-emergence set off a crisis in eastern DRC and led to a spike in tensions with neighbouring Rwanda, which Kinshasa accuses of backing the group.