A Nigerian warplane crashed in Niger on Monday, from where it was conducting military operations in neighboring Mali, and the two pilots were killed, Nigeria's army said in a statement.

The fighter jet was part of Nigeria's air fleet engaged with an African force battling hardline Islamists in Mali. An army source in Niamey said it had suffered a "mechanical" problem.

Five Islamist suicide bombers on Saturday targeted a military patrol near Gao in northern Mali, leaving two Malian soldiers and the attackers dead, a Malian military source said.

"A Malian military patrol was in the village of Hamakouladji (40 kilometers/25 miles north of Gao) this Saturday," the source who requested anonymity told Agence France Presse.

A French soldier was killed Monday in the far north of Mali, the French presidency said.

He was the sixth soldier killed in the west African country since France launched a military intervention in January to quash al-Qaida-linked groups that had taken control of the north.

French Defense Minister Jean-Yves Le Drian said Friday that Mali "cannot have two armies" in the rebel-held city of Kidal, calling for talks with armed Tuareg militants in the war-torn north.

The Tuaregs' National Movement for the Liberation of Azawad (MNLA), which runs Kidal, has refused to give up its weapons or take part in elections planned for July until negotiations have taken place with the Mali government.

Officials charged with organizing elections in Mali have expressed doubts over the ability of the war-torn west African nation to stage a nationwide poll in July.

Mamadou Diamoutani, president of the National Independent Electoral Commission said late Thursday that July 7, the date most often mooted for the first round of a presidential election, "would be a difficult to achieve".

French Defense Minister Jean-Yves Le Drian arrived Thursday in the Malian capital Bamako on the first leg of a tour of several countries to prepare for a post-war Mali, according to an Agence France Presse journalist.

Le Drian, who was greeted by his Malian counterpart Yamoussa Camara, made no comment but his ministry released a statement from Paris saying the trip was preparation for the period after the French withdrawal.

The number of terror attacks in Europe rose significantly last year, the continent's policing agency said Thursday, warning that conflicts in Syria and Mali provided potential breeding grounds for future militants.

In its latest "EU Terrorism and Trend Report", Europol said there had been 219 terror-related attacks in the 27-nation bloc last year in which 17 people died as a result.

The U.N. Security Council on Thursday unanimously agreed to send a 12,600-member international force to Mali to take over from French and African troops battling Islamist guerrillas.

The United Nations is aiming for a July 1 start by the new force, but the 15-nation council will decide later whether the conflict has eased enough for the handover.

Separatist Tuareg rebels in Mali on Wednesday refused to disarm or take part in elections planned for July until negotiations have taken place with Bamako.

"The disarmament of the MNLA (the Tuareg's National Movement for the Liberation of Azawad) is out of the question. Have you ever seen a group disarm without negotiations?" Paris-based spokesman Mahamadou Djeri Maiga told a press conference.

Ousted from their major northern strongholds by a French-led military intervention and all but defeated in their mountain hideouts, Mali's Islamist militants are beginning to regroup at home and abroad.

French and African soldiers have inflicted heavy losses since launching a military operation on January 11 to block the advance of al-Qaida-linked insurgents on the capital Bamako, with Paris claiming to have killed 400 rebels.