At least three Nigerian soldiers and a militiaman were killed in a Boko Haram ambush on the edge of Sambisa forest near the border with Cameroon, military and militia sources told AFP Saturday.

The ambush occurred as troops returned to base late Friday in the town of Gwoza near the mountainous border with Cameroon after destroying three Boko Haram camps in their forest enclave, the sources said.

“We lost three soldiers and a member of the CJTF (anti-Boko Haram militia) in the ambush,” a military officer involved in the offensive said.

“Ten soldiers and three CJTF were injured in the fight,” said the military source who asked not to be identified as he was not authorised to speak.

A militia source backed his account

While returning to base the civilian militia-backed troops came under attack from Boko Haram fighters who “came from all directions”, militiaman Haruna Tola said.

“They came firing heavy weapons from all directions around 6:00 pm (1900GMT) and encircled the team,” Tola added.

Soldiers called in fighter jets for aerial support and succeeded in repelling the attack, he said.

Boko Haram seized Gwoza in August 2014 and declared it their caliphate before Nigerian troops reclaimed it the following March.

The military clawed back the town, 130 kilometres from the regional capital Maiduguri, following intensive military campaigns that saw the jihadists losing swathes of captured territory.

In December last year the Nigerian military claimed it had routed Boko Haram from its Sambisa stronghold after a long offensive and declared the group a spent force.

However, despite the military successes Boko Haram has continued to launch attacks on military targets and raids on villages in the region.