At least eight Nigerian soldiers were killed and several others were missing Friday after being ambushed by IS-affiliated jihadists in violence-wracked northeast Borno state, two military sources told AFP.

A military convoy came under rocket fire by Islamic State West Africa Province (ISWAP) militants as it made its way between the towns of Dikwa and Marte in the Lake Chad region, the sources said.

Eight other soldiers and an anti-jihadist militiaman were injured in the attack, a military officer said.

According to a second military source, who lacked authorization to speak about the incident and asked not to be identified, the jihadists took away two military vehicles and burned three others.

It was the second high-profile attack in less than two weeks by ISWAP jihadists, who are waging a 12-year Islamist insurgency in Nigeria's northeast.

ISWAP has been consolidating territory in the Lake Chad area since rival Boko Haram commander Abubakar Shekau was killed in fighting between the two jihadist forces earlier this year.

Earlier this month, 16 Nigerian soldiers and two anti-jihadist militia were killed in another ambush by IS-allied fighters on their patrol on a highway in northeast Borno state.

ISWAP has recently intensified attacks on civilians along the 135-kilometer (84-mile) Maiduguri-Monguno highway where they set up checkpoints, robbing and killing motorists, according to accounts of local residents.

The near-daily attacks prompted military patrols along the highway, the military sources said.

Since 2019, soldiers have shut down some smaller army bases and moved into larger, fortified garrisons known as "super camps" in an attempt to better resist militant attacks.

But critics say the "super camp" strategy has also allowed militants liberty to move freely in rural areas and left travelers more vulnerable to kidnapping.

The conflict has spilled into neighboring Niger, Chad and Cameroon.

A regional military coalition is fighting the Islamist groups to end their violence.