Fighters loyal to Laurent Nkunda, a renegade general, have signed a peace deal with the government of Democratic Republic of Congo (DRC) and an armed tribal group.
Joseph Kabila, the DRC president, attended the signing in Goma, the capital of eastern North Kivu province, which has suffered heavy fighting in recent months.
The accord on Wednesday followed two weeks of negotiations.
The UN and Western governments, which have exerted heavy diplomatic pressure for a peace deal to be signed, hope the accord can put an end to fighting in the east, which has raged on despite the official end of Congo's 1998-2003 war.
Kabila's government, Nkunda's Tutsi rebels and the Mai Mai militia group had been due to sign the peace deal on Tuesday, but last minute disagreements from Nkunda's side over the draft delayed the signing.
Continuing violence has impoverished the country's east. Up to 1,500 Congolese die in the region every day, mostly from preventable diseases and malnutrition, aid workers say.