Human Rights Watch has warned of a dangerous escalation of tension between ethnic Tutsi and Hutu communities in eastern DR Congo, as a result of fighting involving a militia that Rwanda is accused of backing.
It says the M23 armed group has carried out summary executions and forced recruitment of civilians.
The rights group says the militia is leaving behind a growing trail of war crimes. It wants any military support to Rwanda to be suspended.
The Kigali government has denied backing the M23 group.
Human Rights Watch also says the Congolese army has been working with various armed groups, including Hutu militias, with a record of committing abuses.