Around 15 Islamic militants were killed overnight in heavy fighting with French and Chadian forces in northeastern Mali, French Defense Minister Jean-Yves Le Drian said Tuesday.

The defense ministry has said dozens of Islamists have died in the area over the past few days. A third French soldier died in the conflict on Saturday.

UNESCO is ready to send experts to Mali to assess damage to cultural treasures in the troubled north as soon as security conditions allow, its director general said Monday.

Irina Bokova, on a visit to U.N. headquarters in New York, told journalists UNESCO's action plan for Mali, still was not fully funded.

Mauritanian President Mohamed Ould Abdel Aziz, who has opposed sending troops to combat Islamists in northern Mali, said Monday he would not rule out contributing to a U.N. force if the situation improves.

"If the situation changes... there will be nothing preventing Mauritania, as a U.N. member, from sending troops to the north (of Mali) or in the country's western regions to provide stability and security," he said at a press conference.

An al-Qaida source on Monday confirmed the death of one of the leaders of the organization’s north African wing, in the most significant success yet for the French-led operation against Islamist fighters in Mali.

Al-Qaida in the Islamic Maghreb (AQIM) chief Abdelhamid Abou Zeid was killed as a result of a French bombing raid in the Ifoghas mountains, an AQIM militant told the private Mauritanian news agency Sahara Medias.

At least 50 Al-Qaida-linked rebel fighters have been killed in recent days in clashes with French and Malian troops near the town of Gao in northern Mali, a Malian military source told AFP on Sunday.

"Fighting continues on Sunday morning some 60 kilometers (37 miles) north of Gao between Islamists and Malian troops supported by the French army. We have the situation under control," said a Malian military source contacted by phone from the capital Bamako.

France said Sunday that one of its soldiers had been killed in fighting in northern Mali, in the third death of a French serviceman since the launch of its military intervention in mid-January.

The presidency said in a statement that the soldier, from the First Parachute Chasseur Regiment, was killed in combat on Saturday evening.

Chad has said its troops in northern Mali killed the one-eyed Islamist leader who masterminded an assault on an Algerian gas plant that left 37 foreign hostages dead in January.

The Chadian army, whose troops have been at the forefront of the hunt for Al-Qaida-linked fighters hiding in northern Mali, said Mokhtar Belmokhtar was killed during an operation in the Ifogha mountains on Saturday.

Algerian officers have found a weapon that belongs to a top al-Qaida operative reportedly killed in Mali and examined a body but are still unable to confirm it is his, a daily said on Saturday.

El Khabar's report comes a day after Chadian President Idriss Deby Itno said that Abdelhamid Abu Zeid was killed in deadly fighting between Chadian troops and Islamist fighters on February 22 in northern Mali.

The United States finds reports that one of the most notorious leaders of al-Qaida's North African wing has been killed in fighting with French troops "very credible," an official said Friday.

Speaking on condition of anonymity because the report has not been formally confirmed, the U.S. official said that if Abdelhamid Abou Zeid was indeed slain in Mali "it would be a significant blow to al-Qaida in the Islamic Maghreb."

Malian troops have arrested about 50 people on an island in the Niger river that was used as a hide-out by armed Islamists in northern Mali, military sources told Agence France Presse Friday.

On Friday morning, an AFP correspondent on the island of Kadji, near the town of Gao, saw two boats filled with prisoners, all bearded and with shaved heads, crossing the Niger.