Three Chadian UN peacekeepers were killed and four injured in an attack on a UN convoy in northern Mali, a peacekeeping mission there said late Sunday.

In a statement, the United Nations Integrated Stabilization Mission for Mali (MINUSMA) said the incident took place near Aguelhok in the Kidal region.

Kidal is the former stronghold of separatist rebels in Mali. But several militant groups are active in the north despite a 2015 peace agreement between the Malian government and Tuareg rebel groups.

Mahamat Saleh Annadif, head of the mission, condemned the attack against civilians and UN operations in the West African country.

"We will have to combine all efforts to identify and apprehend those responsible for these terrorist acts," Annadif said.

''The Secretary-General expresses his deep condolences to the families of the victims, as well as the Government and people of Chad. He wishes a speedy recovery to the injured,'' Stephane Dujarric, spokesman for the secretary-general, said in a separate statement.

''The Secretary-General reaffirms that such cowardly acts will not deter the United Nations from its resolve to continue supporting the people and Government of Mali in their pursuit of peace and stability,'' he added.

No group has yet claimed responsibility for the attack, but similar attacks are usually claimed by militias linked to Al-Qaeda in the Islamic Maghreb (AQIM).

Mali, one of the poorest countries in the world, suffers from the presence of several terror groups, and French, Malian, and UN peacekeepers carry out counter-terrorism operations there.

Tensions erupted in Mali in 2012 following a failed coup and a Tuareg rebellion that ultimately allowed al-Qaeda-linked militant groups to take over the northern half of the country. In 2015, a peace deal was signed between the government and some insurgent groups.

Political and community disputes continue to fuel tensions in the West African nation, thus undermining the implementation of the peace agreement.