At least five United Nations peacekeepers have been killed in an attack on their base in northeastern Mali, the UN said.
Eight mortar shells were fired at the base and there was also gunfire, said Olivier Salgado, a spokesman for the UN peacekeeping mission, whose acronym is MINUSMA.
"At about 7am, the MINUSMA base in Kidal was the target of a complex attack," said Mahamat Saleh Annadif, the Mali representative of UN Secretary-General Ban Ki-moon.
A statement issued by the secretary-general's office said "attacks targeting United Nations peacekeepers constitute war crimes under international law".
"The secretary-general reiterates that attacks against MINUSMA will not weaken the determination of the United Nations to support the Malian government, the parties to the peace agreement, and the people of Mali in their efforts to achieve lasting peace and stability."
A Guinean member of the UN force told the AFP news agency that the dead soldiers were from his country's contingent, adding that seven of the wounded men were "in serious condition".
Radouane Ag Mohamed Aly, spokesman for the Coordination of Azawad Movements, a rebel group made up of ethnic Tuaregs that has previously been accused of having links with al-Qaeda in the Islamic Maghreb group, told the Reuters news agency that Friday's attack had been conducted by rebels.
However, there was no official confirmation or claim of responsibility for the Kidal attack.
The UN base is part of an attempt by the UN to end violence in Mali following a takeover of the north by rebels in 2012. A year later a French-led intervention force pushed the armed separatists out of key towns in the region.
The UN mission has not stopped the violence and rebels have expanded their attacks in recent months into other parts of Mali and beyond.
These have included an attack on a hotel in Mali's capital Bamako in November, in which 20 people died, and one on Burkina Faso's capital Ouagadougou in January, in which 30 were killed.
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Source: Al Jazeera and agencies