Islamist Militants killed six soldiers and a civilian militia leader as they hit three towns in Nigeria's conflict-torn northeastern state of Borno, security sources and residents told AFP on Friday.
Several troops and militiamen are also missing, they said.
Suspected fighters from Islamic State West Africa Province (ISWAP), affiliated to the so-called Islamic State group, attacked the town of Gubio around 1630 GMT on Thursday, unleashing a battle with security forces.
"The bodies of six soldiers and the (local) head of the Civilian Joint Task Force (CJTF) were recovered outside the town with bullet wounds," a security source said.
The Islamist Militants stormed into Gubio aboard a dozen pickup trucks mounted with machine guns, according to local resident Idrissa Kaka, who confirmed the death toll.
They also made off with three military vehicles and a van belonging to the CJTF.
"The whereabouts of the remaining soldiers is unknown. Our fear is that they were captured along with the vehicles," he said.
The Islamist Militants then attacked the towns of Gajiganna and Gajiram, where they torched buildings and sent soldiers fleeing, residents said.
Gubio, which lies 80 kilometres (50 miles) north of Borno state capital Maiduguri, has been repeatedly targeted by the jihadists.
Last month six people including three soldiers were killed when ISWAP attacked military base in the town.
Since July last year ISWAP has intensified attacks on military targets, raiding bases and ambushing military patrols.
Boko Haram fighters loyal to long-time factional leader Abubakar Shekau -- who are notorious for killing civilians -- have also carried out attacks on the military.
The decade-long Islamist Militants insurgency in northeast Nigeria has claimed more than 35,000 lives and left more than two million people displaced from their homes.
The conflict which spilled into neighbouring Niger, Chad and Cameroon and has resulted in a severe humanitarian crisis in the region, leaving millions reliant on food aid in displacement camps.