Militants linked to al Qaeda and a Tuareg-led separatist group ambushed a military convoy in northern Mali over the weekend, and a source close to the rebels said more than 50 soldiers and allied Russian fighters were killed and others taken hostage. 

The attack marked the latest in a series of escalating assaults by the two groups, which joined forces for nationwide attacks in April that killed the defence minister and hit the airport in the capital Bamako, and launched a second wave this month aimed at seizing the town of Anefis.

The incident occurred on Saturday between Anefis and the city of Gao in the north, according to statements from Mali's armed forces, the Azawad Liberation Front (FLA), and the al Qaeda-linked group Jama'at Nusrat al-Islam wal Muslimin (JNIM).

Mali's army said the ambush happened in the Tabrichat area and was followed by retaliatory airstrikes that killed at least 20 insurgents.

The FLA statement said "dozens" of Malian soldiers and members of the Russian paramilitary Africa Corps had been "neutralised" and that there was considerable material damage.

A source close to the FLA said more than 50 pro-government fighters were killed. Reuters could not independently confirm the death toll.

JNIM shared footage online that appeared to show soldiers surrendering following the ambush, with their hands behind their heads, as well as rebels firing at some of their captives. Reuters has not independently verified the footage.

The army has so far retained control of Anefis.

The mounting violence poses a threat to Mali's military-led government which took power in coups in 2020 and 2021 and promised to improve security in the landlocked Sahel country.