All sides in eastern DR Congo have committed serious human rights abuses, the UN secretary general has said.
Ban Ki-moon said both government forces and rebels loyal to Gen Laurent Nkunda had carried out arbitrary executions, mass killings, rape and torture.
The report covers July to November, when the most recent fighting flared.
In a separate report, a rights group has accused the government of using violence to eliminate political opponents following polls in 2006.
Human Rights Watch (HRW) said Congolese security forces had deliberately killed more than 500 people in a campaign against opposition groups.