Dissident CDNP leader Bosco Ntaganda declared the ceasefire
Senior officers of the main Tutsi rebel group in the east of the Democratic Republic of Congo have announced a ceasefire with government forces.
The breakaway faction of the National Congress for the Defence of the People (CNDP) said its fighters would join the Congolese army.
The move is expected to increase pressure on CNDP leader Laurent Nkunda to declare a full ceasefire.
Some 250,000 people have been displaced by fighting which erupted in August.
Gen Nkunda says he is fighting to protect his Tutsi community from attacks by Rwandan Hutu rebels based in DR Congo, some of whom are accused of taking part in the 1994 genocide.
The ceasefire was announced at a meeting in the eastern city of Goma attended by nine top rebel commanders, said Rwanda's army chief of staff and the Congolese interior minister.
Dissident CNDP leader Bosco Ntaganda said: "We declare the end of hostilities between CNDP forces and government troops."
The presence of Rwanda's army chief of staff was significant, as Rwanda has often been accused of using the CNDP as a proxy for interfering in its neighbour's affairs, says the BBC's Peter Greste in Nairobi.
Gen Nkunda was absent. Talks between his supporters and the government were suspended in Nairobi earlier this week.
Gen Nkunda's loyalists said they would react to the dissident faction's declaration over the weekend.
Earlier this month Mr Ntaganda said he had overthrown Gen Nkunda.
Our correspondent says it is not clear if he accepts the ceasefire or if this is a manifestation of an apparent split within the rebel group.
Sources in Goma say it does appear to involve all the CNDP forces, our correspondent adds.
The ceasefire does not mean the violence in DR Congo is at an end though. The region is home to a host of other militias, including remnants of the Interahamwe, the Hutu radicals behind Rwanda's genocide.