Nigeria’s military said on Thursday it had killed more than 50 jihadists in coordinated clashes with insurgents who attacked several army bases in the country’s volatile northeast.

Troops, supported by fighter jets, engaged the attackers in the early hours of Thursday after they launched simultaneous assaults on military bases in Dikwa, Mafa and Gajibo in Borno state, as well as Katarko in neighbouring Yobe state, according to a statement by military spokesman Lieutenant Colonel Sani Uba.

“The combined ground and air efforts resulted in the neutralisation of over 50 terrorists across all the locations,” Uba said, adding that several soldiers were wounded, though he did not specify how many.

Authorities did not identify which faction carried out the attacks, but intelligence sources told AFP that Islamic State West Africa Province (ISWAP) militants were responsible.

Uba said parts of the military defences in Mafa and Dikwa were briefly breached during the fighting, with several vehicles and buildings destroyed by fire from the militants’ armed drones and rocket-propelled grenades.

Residents in Mafa showed AFP images of charred trucks that militants had set ablaze. Locals said the vehicles, mostly carrying cement to Chad, had been parked overnight as drivers avoided travelling due to the threat of insurgent attacks.

Nigeria has been battling Boko Haram and its ISWAP offshoot for 16 years. The insurgency, which aims to establish a caliphate in the northeast, has killed more than 40,000 people and displaced around two million. The conflict has also spread to neighbouring countries, prompting the creation of a regional military coalition to combat the Islamist groups.