M23 military chief Col Sultani Makenga
At least eight people have been killed in the first clashes between rival factions of the M23 rebel group in DR Congo, sources have told the BBC.
The violence was linked to a power-struggle between M23 political leader Jean-Marie Runiga and military chief Sultani Makenga, the sources said.
On Sunday, regional leaders signed a UN-brokered accord to end conflict in eastern Democratic Republic of Congo.
About 80,000 people have been displaced in fighting since May 2012.
The M23 launched a rebellion against the DR Congo government, briefly seizing Goma, the main city in the east, in November.
Both Rwanda and Uganda strongly deny claims they back the rebels.