Nigeria's military says it has killed 50 Boko Haram fighters in an operation launched in response to an attack on civilians in the northeast.
The military sent troops in pursuit of the attackers backed by air support, the area military spokesman Sagir Musa told the AFP news agency in the northeastern city of Maiduguri on Friday.
"Troops pursued the terrorists to their camps with air support and about 50 insurgents were killed in a shootout," Musa said.
"Troops are pursuing the remnants of the fleeing terrorists by blocking all possible escape routes."
On Thursday, suspected Boko Haram members disguised as traders invaded an open market and opened fire, killing at least 15 people in the village of Gajiram, in the Borno state, witnesses and security operatives said.
Borno state is Boko Haram's historic stronghold and where the military has battled fighters for the past four years.
Most of the northeast was placed under a state of emergency in May, when the military launched a major offensive aimed at crushing the group.
The phone network has been shut down in Borno state since the emergency measures were imposed and details of both attacks by armed groups and military operations have been slow to emerge and difficult to verify.
Boko Haram claims it is fighting to create an Islamic state in northern Nigeria, though it is believed to have a number of factions with varying aims.
Its insurgency is estimated to have cost more than 3,600 lives, including killing by the security forces, who have been accused of major abuses.