At least 20 people were killed when Nigerian troops battled Boko Haram terrorists who attacked Damboa town in the troubled Borno State in Nigeria’s North-East over the weekend.

A statement by a military spokesman quoted by Reuters news agency said the clash was triggered after Boko Haram warriors crept into Damboa in the early hours of Saturday, killing five worshippers at a mosque as they said their morning prayers.

“While they were unleashing their mayhem, troops … engaged the terrorists, killing 15 in the process while others fled,” Captain Aliyu Danja said in a statement obtained by Reuters.

Boko Haram, which is fighting to Islamise Nigeria, has proved difficult to overcome despite a concerted military offensive following a state of emergency imposed in the North-East last May by President Goodluck Jonathan.

Nigerian fighter jets last week bombed the sect’s camps in response to a massacre of students at an agricultural college that killed at least 41.

•Photo shows a group of Boko Haram’s fighters.