"Yesterday (Saturday) morning, a food convoy escorted by volunteers for the defence of the fatherland (VDP) was the target of an ambush on the Dori-Gorgadji road," during which "12 people were killed," a security source said.

A local official confirmed to AFP that 10 back up troops had "fallen".

Jihadist groups affiliated with Al-Qaeda and the Islamic State group have regularly carried out attacks in northern and eastern Burkina Faso since 2015, killing more than 2,000 people and displacing almost two million.

Unrest linked to jihadist groups also plagues Burkina Faso's West African neighbours Mali and Niger.

The three land-locked countries rank among the poorest in the world and their armed forces are ill-equipped against a foe skilled at hit-and-run raids, ambushes and planting roadside bombs.

In December 2019, Burkina set up the VDP auxiliary force, which is among the units that has suffered most losses.

Recruits are given two weeks' military training and then work alongside the army, typically carrying out surveillance, information-gathering or escort duties.