PARIS: Clashes between French troops and Islamist fighters in Mali killed a French soldier and around 10 rebels, defence officials said Wednesday, as President Francois Hollande claimed the operation had wiped out "terrorist kingpins".

Hollande did not name the Islamist leaders killed in operations in the Ifoghas mountains in Mali's far northeast, prolonging doubt around Chad's claims that its forces have killed Mokhtar Belmokhtar, the mastermind of a January raid on an Algerian gas plant that left 38 hostages dead.

"The terrorist kingpins have been destroyed," Hollande said during a visit to Warsaw for a six-nation European Union defence summit.

The French leader, whose decision to intervene in Mali nearly two months ago has so far met broad approval at home, also said France would begin pulling its troops out in April, a month later than previously announced.

The "final phase" of the French intervention in the troubled west African country "will last through March and from April there will be a decrease in the number of French soldiers in Mali as African forces will take over, supported by the Europeans," he said.

France had said in early February that French troop numbers -- now around 4,000 -- would decrease from March if all went according to plan.

But the French-led operation, which initially met little resistance as it pushed Al-Qaeda-linked Islamists from the northern towns they had occupied for 10 months, has since come under attack in insurgent-style guerrilla raids and suicide bombings.

Paris is keen for the United Nations to incorporate some 8,000 African troops currently being deployed to Mali into a UN peacekeeping force.

Hollande's remarks came after Sergeant Wilfried Pingaud, 37, became the fourth French soldier to die in action since the intervention began. He was a member of the 68th African Artillery Regiment based in Valbonne in the south of France.

Pingaud died in exchanges with a group of Islamist fighters that erupted as French and Malian troops carried out an operation to secure an area about 100 kilometres (65 miles) east of Gao, the largest city in the north.

Four Malian soldiers were wounded in the clash.

Hollande said Pingaud had "carried out his mission to free Mali of terrorist groups with courage and devotion."

France has suffered relatively few casualties during its operations, launched on January 11 to fight back Islamist rebels who had threatened to advance on the former French colony's capital, Bamako.

Army spokesman Colonel Thierry Burkhard said "half a dozen" Islamists had surrendered to French forces following fighting near Tessalit on the northern edge of the Ifoghas range, where troops are working to hunt down militants hiding out in the mountainous terrain on Mali's northeastern border with Algeria.

France said Tuesday that "dozens" of rebels had been killed in fighting in the Ifoghas in recent days.

Chad, which has done much of the frontline fighting, has confirmed the death of 27 of its troops in the clashes.

Chadian President Idriss Deby Itno on Monday reiterated that Belmokhtar, the orchestrator of the In Amenas gas plant bloodbath, had been killed during fierce fighting in recent days, but French Defence Minister Jean-Yves Le Drian said Tuesday the report was unconfirmed.

An Al-Qaeda in the Islamic Maghreb (AQIM) source who on Monday confirmed the death of another top militant, Abdelhamid Abou Zeid, insisted that Belmokhtar was still alive and fighting.

-- Reconciliation commission --

In Bamako, interim president Dioncounda Traore's cabinet announced the creation of a 33-member "reconciliation and dialogue commission" to try to restore peace among the different groups in the country.

The commission will investigate "cases of human rights violations committed in the country since the beginning of hostilities", the government said.

Mali's plunge into crisis began with a separatist rebellion among the north African Tuareg people.

The army's humiliation at the hands of the rebels led a group of mid-level officers to overthrow the government in March 2012, opening a power vacuum that a trio of Al-Qaeda-linked Islamist groups exploited to seize control of the vast desert north.

A group of 24 accused Islamist rebels detained in northern Mali have so far come before judges on charges including terrorism and illegal weapons possession, prosecutors said Wednesday.