A UN peacekeeper was killed and three others injured Wednesday in a "terrorist attack" on their convoy in Kidal, northern Mali, a MINUSMA spokesperson said on Twitter.

The casualties were members of the mission's Jordanian contingent, a security official said separately on condition of anonymity.

The convoy was hit by small-arms fire and rocket-propelled grenades in an attack that lasted about an hour, MINUSMA spokesman Olivier Salgado tweeted.

"Unfortunately, one of the blue helmets succumbed to his wounds following the attack," he posted in French.

No details were given about the suspected attackers.

MINUSMA -- the United Nations Multidimensional Integrated Stabilization Mission in Mali -- was deployed in 2013 to help shore up the fragile Sahel state in the face of jihadist attacks.

With 13,000 members, the mission is one of the UN's biggest peacekeeping operations, and also one of its most dangerous. It says 172 troops have died from hostile acts.