Terrorists affiliated with the Islamic State group have killed six soldiers in a raid on a military base in northeastern Nigeria, two military sources confirmed to AFP on Monday.

The attack occurred early on Sunday, when fighters from Islamic State West Africa Province (ISWAP) launched a coordinated assault on the base in Sabon Gari, located in the Damboa district of Borno State.

The militants arrived in trucks and on motorcycles, the military sources said, speaking on condition of anonymity.

The attackers set fire to the base and destroyed army vehicles during the raid, the sources added.

“We lost six soldiers in the ISWAP terrorist attack on the base after an intense gun battle,” one military officer said, describing the heavy fighting.

The soldiers were ultimately forced to retreat, according to the officer.

In response, fighter jets were deployed from the regional capital, Maiduguri, about 100 kilometers (62 miles) away, and struck the retreating militants.

The second military officer, who provided the same casualty toll, said, “Air strikes against the fleeing terrorists resulted in multiple militant fatalities and the destruction of operational vehicles and their weaponry.”

However, the officer did not provide details on the number of ISWAP casualties.

Air strikes kill fleeing ISWAP terrorists after deadly raid on Borno military base