UPDATE: Three killed as military helicopter explodes in Adamawa

An Airforce helicopter involved in the fight against Boko Haram crashed and exploded in Yola, Adamawa on Thursday, killing all three crew members on board. But reports said the crash occurred in an area where there were no immediate cases of combat or of Boko Haram activity.

The army said in a short statement on Friday: "A ground attack helicopter on an armed patrol crashed around the Federal University of Technology Yola, Adamawa State. The crew of 3 was lost in the ill-fated accident”

It was not immediately clear if the helicopter had been shot down or crashed because of technical failure.

It was the second Nigerian military helicopter to go down this week in Yola, in Adamawa State. Another, according to the defence ministry, made a forced landing shortly after takeoff.

Reuters further reports: “The helicopter may have been heading for a military operation further north from Yola where the military were fighting Boko Haram. The army retook control of the towns of Mubi and Maiha from the insurgents with the help of local hunters and civilian vigilantes on Thursday.

But there was still signs of rebel activity near this area.

A resident of Gombi, situated west of Mubi and Maiha, told Reuters that there was heavy fighting between the army the insurgents around the town on Friday.

North of Gombi, about 30 Boko Haram militants stormed the village of Chibok, in Borno State, where the group abducted some 200 schoolgirls seven months ago, raising international outcry. Chibok has been target of a number of attacks since the abductions.

"The insurgents arrived at about 5pm on Thursday, shooting sporadically, forcing people to flee into the bush," a villager who fled told Reuters by telephone, adding that many villagers may have been killed".