Sunday  was a black day for four Nigerian troops who were killed in an ambush by fighters suspected to be from an IS-affiliated jihadist faction in the country’s restive northeast, two military sources said.

The attackers who were believed to be from the Islamic State West Africa Province group opened fire on a military patrol in Mogula village close to the border with Cameroon, killing four soldiers and seizing two machine guns, one of the military officers said.

“Our troops came under attack by ISWAP terrorists in Mogula in an ambush in which we lost four soldiers,” the first source said.

“The attack happened around 11:00 hours when the team was on routine patrol in the area,” the officer said.

The second officer gave the same toll and said the jihadists seized two military pickups but were forced to abandon them as they slowed their escape due to the poor state of the road.

“They, however, dismantled the anti-aircraft guns mounted on the two vehicles and went away with them,” he said.

The sources asked not to be identified because they were not authorized to speak on the incident.

The decade-long jihadist insurgency in northeast Nigeria has claimed over 27,000 lives and forced around two million people from their homes.

ISWAP split from the Boko Haram faction controlled by longtime leader Abubakar Shekau in 2016.

The IS-linked fighters have in recent weeks been asserting their presence in areas near the border with Cameroon controlled by Shekau’s group.