Two people were killed in fighting in the capital of the Central African Republic and six peacekeepers from Burundi and Cameroon were wounded in an ambush, a spokeswoman for the United Nations mission in the country said on Saturday.
The violence follows days of fighting that threatens the interim government of President Catherine Samba-Panza, who took office in January aiming to end two years of unrest in which thousands have died and more than 1 million have fled.
Samba-Panza said she would not step down in the face of heightened political pressure, and there were signs late on Saturday that tensions could be easing as one militia group withdrew its call for her resignation.
The unrest is a struggle for power and resources in an impoverished country with reserves of gold and diamonds. Rival communities have also clashed across religious lines.
Those killed overnight include a gendarme and a local leader for a militia known as "anti-balaka," whose adherents follow Christianity and animism.
The United Nations took over peacekeeping in mid-September from a mission run by the African Union. The country was plunged into chaos as mostly Muslim rebels from a coalition called the Seleka seized power in March 2013. Its rule was marked by abuses that prompted a backlash. France sent troops to its former colony and an existing African peacekeeping force was beefed up.
Sporadic violence has continued despite the Seleka leader's resignation from the presidency in January.