"The United Nations launched an operation by sending out a patrol," after the Bangui prosecutor's office issued an arrest warrant for a former leader of the mainly Muslim Seleka rebel alliance, which seized power in 2013 before being forced to step aside last year, a UN MINUSCA force officer said.

"As the (UN) blue helmets approached the area, they were targeted by armed individuals and responded," the officer told AFP.

"There was one death on the side of the MINUSCA blue helmets and at least eight other people shot and wounded... A UN force vehicle was seriously damaged," he added, without giving a nationality for the dead man.

Residents in the KM5 district where the trouble occurred confirmed by phone that an exchange of fire had taken place, leaving several civilians wounded by gunfire.

"Tension remains high" in the area with shops and markets closed, one said.

Security Minister Dominique Said Paguindji said operations were ongoing, without confirming the casualties.

"Once calm and security are restored... we can look at the operational toll" he added.

The 2013 coup ousted president Francois Bozize and pushed the country into a conflict that took on an unprecedented religious dimension, pitting sections of Christian and Muslim populations against one another.

Largely Christian "anti-balaka" -- or anti-machete -- militias were formed to avenge atrocities by the Seleka rebels behind the coup, resulting in waves of killing, rape and pillaging since.

The Central African Republic is set to hold elections in October, but the polls have already been pushed back three times as the former French colony grapples with its worst crisis since independence in 1960.

Hundreds of thousands of people have fled deadly civil unrest in the landlocked nation since 2013, with the upcoming vote seen as a key test for the prospects of reconciliation.

Earlier this month the UN said it was "alarmed" that authorities in the country planned to block refugees from voting in the October polls, with nearly 200,000 mostly Muslims citizens facing exclusion.