Chad announced it is closing its border with the Central African Republic on Monday, saying it wants to stop violence spilling over from the sectarian conflict next door.

"We will not allow the Chadian territory to be used by one side or the other to wreak havoc in this brotherly country," said government spokesman Hassan Sylla Bakari.

Central African Republic's ex-Seleka fighters on Saturday named Joseph Zoundeko as their new military leader in a bid to unite the mostly Muslim rebel group amid ongoing sectarian violence in the war-torn country.

One hundred ex-Seleka officers attended the two-day meeting in the northeastern town of Ndele including Nourreddine Adam, the right-hand man of former president Michel Djotodia, who seized power in March last year in a political coup that plunged Central Africa into chaos.

Central African Republic President Catherine Samba Panza said on Saturday she will "reshuffle" her government amid continuing sectarian violence, more than three months after she came to power.

In an interview with Agence France Presse, Samba Panza said ministers in her government must "make an assessment of their actions".

The U.N. Security Council ordered sanctions Friday against three Central African Republic leaders, including former president Francois Bozize.

The leader of the anti-Balaka militia Levy Yakete and the Seleka militia's number two Nourredine Adam were also targeted.

A team from the International Criminal Court arrived in war-torn Central African Republic on Thursday on a first mission to investigate crimes committed in the country since bloodshed broke out in 2012.

"Serious crimes have been committed since 2012 in Central Africa," ICC head of international cooperation Amadi Bah said at a news conference in the capital Bangui.

French troops had to call for air backup to fight off an assault by well-armed militants in the Central African Republic on Monday in clashes that left several gunmen dead, the military chief of staff in Paris said.

Around 40 heavily-armed militants riding motorcycles and pick-up trucks attacked the French peacekeepers on a road leading to the village of Boguila in the northwest of the strife-torn country, a spokesman told AFP.

The international charity Doctors Without Borders (MSF) said Monday it will temporarily cut back its work in the strife-torn Central African Republic after a bloody attack on a hospital.

"In protest against the brutal killing of 16 civilians, including three of its humanitarian workers at Boguila Hospital on 26 April, MSF is reducing its activities in CAR and related projects in neighboring countries for one week to emergency medical care only," it said in a statement.

Almost 30 people, mainly civilians, have been killed in several days of fighting between rival factions in the Central African Republic, an African military source said Monday.

The clashes erupted on Thursday in the Mala region around 200 kilometers (120 miles) north of the capital Bangui between Seleka rebels and the Christian vigilante groups known as the anti-Balaka, an official from the African peacekeeping force MISCA told Agence France Presse.

The United Nations is considering the use of unarmed drones to monitor sectarian violence in the Central African Republic, a U.N. official said Saturday, ahead of the deployment in September of 12,000 peacekeepers in the restive nation.

U.N. under-secretary-general for peacekeeping operations Herve Ladsous said he was thinking about the possible deployment of unmanned aircraft systems to see what is happening on the ground.

The European Union force sent to help stem deadly sectarian violence in the Central African Republic is operational and has been deployed at Bangui airport, EU sources said Wednesday.

The troops are taking over airport security from French soldiers who will be deployed elsewhere in the strife-torn country.