Fighting erupted late Saturday when troops ambushed a convoy of the Islamic State West Africa Province (ISWAP) near Jakana village, 42 kilometres (26 miles) from the state capital Maiduguri.

"We lost four soldiers and a member of the vigilante group in the fighting," a military officer said in reference to an anti-jihadist militia in the region.

"The terrorists came in large numbers and our troops fought gallantly but they were overwhelmed," added the officer who asked not to be identified for fear of sanction.

Several troops were also injured and four trucks were lost to the militants, he said.

The jihadists were riding in pick-up trucks fitted with machine guns according to an anti-jihadist militiaman who confirmed the death toll.

In a statement issued Sunday, the Nigerian military said seven jihadists were killed and eight injured when their vehicle hit a landmine during a clash near Jakana on Friday.

The improvised explosive device had been planted by the jihadists, army spokesman Colonel Aminu Iliyasu was quoted as saying. He called the blast a "tactical boomerang".

Jakana lies on a 120-kilometre highway that links Maiduguri and Damaturu, the capital of Yobe state.

Jihadists have raided military bases and attacked troops and motorists along the highway in the past.

In July, six soldiers died during a gun fight outside Jakana.

The decade-long conflict which spilled into Nigerian neighbours -- Niger, Chad and Cameroon -- has killed at least 35,000 people and forced some two million to flee their homes in Nigeria alone.