Clashes between Nigeria's military and Islamist extremist group Boko Haram in two northeastern towns have left at least 35 people dead, most of them insurgents, the army said on Monday.

A clash in the town of Bama sparked by an attack on a police base "led to the death of one policeman and 17 Boko Haram terrorists," a military statement said. Fighting in the town of Malam Fatori "led to the death of two soldiers and 15 Boko Haram terrorists," it said. Both incidents occurred on Sunday.