At least 20 people have been killed in clashes between rival factions of Burundi's last rebel group, police say.
These are the worst clashes in Bujumbura for a year
Hundreds of people have fled their homes near the scene of the fighting in the northern outskirts of Bujumbura.
Two rival factions of the National Liberation Front (FNL) are engaged in a power struggle.
These are the worst clashes in the capital for more than a year, raising fears of a return to ethnic violence which has blighted Burundi since 1993.
"So far we have found 21 bodies," police officer Anaclet Nindabire told the AFP news agency.
An AFP reporter said 11 bodies still lay on the streets and rice fields in Buterere, north-west of Bujumbura.
One faction is trying to oust FNL leader Agathon Rwasa. They want to implement a cease-fire deal which he pulled out of in July.
Pierre Nkurunziza, leader of the FDD former rebels, was elected president in 2005 after a lengthy peace process boycotted by the FNL.
Burundi has been plagued by tension between the dominant Tutsi minority and the Hutu majority since independence in 1961.
More than 300,000 people died in the war sparked in 1993 by the assassination of Burundi's first Hutu head of state and democratically-elected president, Melchior Ndadaye.