Fighters from Islamic State-West Africa Province (ISWAP) opened fire Friday with heavy guns on a motorcycle convoy of Nigerian troops, anti-jihadist militia and local hunters on patrol in Damboa district, according to a military source and a security report.

The incident is the latest in dozens of attacks targeting Nigerian security forces by ISWAP, which has recently intensified raids on military bases with rocket-propelled grenades and suicide drones.

"We lost two soldiers and two members of the Civilian CJTF (militia) in the ambush by ISWAP terrorists," a military officer told AFP.

"The terrorists laid ambush on the patrol convoy of motorcycles led by the brigade commander, which resulted in exchange of fire," said the officer, who asked not to be identified because he was not authorised to speak on the incident.

A United Nations situation report shared among aid agencies in the region and seen by AFP confirmed the killing of two soldiers and two anti-jihadist militia members in the ambush, while 17 motorcycles were seized by the jihadists.

According to the report, several soldiers, including the military commander, were missing, but the commander returned to base in the town of Damboa, 90 kilometres (55 miles) from the regional capital, Maiduguri.

The attack underlines the threat ISWAP poses in the region despite being locked in internecine infighting with rival jihadist group Boko Haram for control in areas around Lake Chad.

ISWAP split from Boko Haram in 2016 due to ideological differences and rose to become a dominant group in the region.

The group has been under pressure from Boko Haram, which has pushed it from most of the islands in Lake Chad under its control.

On Sunday, Boko Haram killed around 200 ISWAP fighters in an ambush on the shores of the lake, according to intelligence and anti-jihadist militia sources.

The jihadist violence has killed more than 40,000 people and displaced around two million in the northeast since it erupted in 2019.

The conflict has spilled into neighbouring Niger, Cameroon and Chad, leading the region to launch a military coalition to fight the jihadist groups.