French soldiers have killed unidentified fighters in the capital of the Central African Republic near the airport, a French army spokesman told the Reuters news agency.

The army shot the men in clashes early on Thursday in Bangui, the official said.

More French troops rumbled into the country on Friday, trying to stop violence in the capital a day after armed Christian fighters raided Muslim neighbourhoods, leaving at least 185 people dead.

France began sending reinforcements within hours of a UN vote on Thursday authorising its troops to try to stabilise the country.

However, French officials insisted the mission's aims were limited to bringing a minimum of security to Bangui, where people now fear to leave their homes, and to support an African-led force.

"You have to secure, you have to disarm," Jean-Yves Le Drian, French defence minister, told Radio France Internationale. "You have to ensure that the vandals, the bandits, the militias know they can't use the streets of Bangui for their battles."

The streets of Bangui were deserted on Friday morning, with the only vehicles on the road belonging to either international security forces or the rebel fighters who claim control of the government.

There was no repeat of the clashes, Le Drian said.

Joanna Mariner, part of an Amnesty International team in Bangui, said that she had reports of pillaging and killing in the third district. "The French are patrolling on the main axes, but the city isn't yet secure," she added.

The Archbishop of Bangui said 39 people were killed overnight and on Friday. Meanwhile, clashes also continued in

Bossangoa, to the north, where at least 30 people had been killed, according to an aid worker.

The former French colony has slipped into chaos since mainly Muslim rebels seized power in March, leading to tit-for-tat violence with the Christian majority. The violence on Thursday was the worst the capital has seen during the crisis.

Since 2011, France has intervened in four African countries, in Ivory Coast, on a joint mission in Libya, in Mali and now in Central African Republic.