Boko Haram

MAIDUGURI, Nigeria (Reuters) - Boko Haram rebels killed four Nigerian soldiers in a night ambush outside the northeastern city of Maiduguri and several insurgents also died in the firefight, according to a statement on Wednesday from Defence Headquarters.

Soldiers fired shots in the air at Maiduguri barracks on Wednesday because they were angry with their commanders about having been made to return at night to the city through an area where Boko Haram is fighting an insurgency, soldiers told Reuters.

"Troops on patrol around Chibok were ambushed by insurgents yesterday. Troops engaged the insurgents in a fierce combat and extricated themselves from the ambush killing several insurgents. Four soldiers however lost their lives during the ambush," said a statement from Defence Headquarters.

"On evacuation of the remains of the fallen troops, the General Officer Commanding addressed the troops who registered their anger about the incident by firing into the air. The situation has since been brought under control," it said.

Boko Haram has waged a five-year insurgency in northern Nigeria for an Islamic state. A month ago its fighters stormed a school in the village of Chibok and seized 276 girls who were taking exams. Some escaped but about 200 remain missing.

On Monday, Boko Haram leader Abubakar Shekau released a video showing some of the girls in captivity and offered to exchange them for Boko Haram prisoners held by the government.

(Reporting by Lanre Ola and Isaac Abrak; Writing by Matthew Mpoke Bigg; Editing by Andrew Roche)