At least two civilians were killed and 13 others injured when militants attacked a military checkpoint in northeast Nigeria, a local government spokesman and residents said Tuesday.
Fighters from the Islamic State West Africa Province (ISWAP) in 14 trucks launched an attack on soldiers in Maina Hari village near Biu Town, 180 kilometres southwest of the Borno State capital, Maiduguri.
Civilians were caught in the crossfire during the fierce two-hour battle that followed.
"Two persons died," Bulama Talba, a Borno government spokesman said in a statement, after visiting the Biu general hospital where casualties were being treated on Tuesday.
"Thirteen persons sustained various degrees of injuries as a result of stray bullets while trying to escape," Talba said.
However local residents said three people from the same family were killed during the fighting when a rocket-propelled grenade hit their home nearby.
"Two RPGs (rocket-propelled grenades) hit two houses, killing three people in one and badly damaging the other along with a vehicle," said Ahmad Babagana, a local resident who visited the scene.
The militants were forced to withdraw, civilian militia fighter, Mustapha Karimbe said. There were no reports of combattant casualties on either side, he added.
In recent weeks, ISWAP, an off-shoot of Boko Haram, has intensified deadly attacks in the northeast, targeting soldiers but also mounting fake checkpoints and killing and abducting civilians.
On Tuesday the United Nations condemned the "increasing practice by armed groups to set up checkpoints targeting civilians" in the northeast.
On Sunday dozens of ISWAP militants made a failed attempt to overrun the city of Damaturu, the capital of neighbouring Yobe State.
Soldiers helped by fighters jets fought off the militants during a prolonged battle in which several militants were killed, according to multiple security and civilian sources.
The decade-long insurgency in northeast Nigeria has killed 36,000 people according the UN and displaced a further two million, sparking a prolonged humanitarian crisis.
The conflict has spilled into neighbouring, Niger, Cameroon and Chad, leading the countries to form a regional military force to combat the threat.