Suspected Islamist militants have reportedly killed at least 20 Nigerian soldiers, including a commanding officer, following an assault on an army base in a remote town in northeastern Borno state, according to security sources and local residents on Sunday.

Boko Haram and the Islamic State West Africa Province (ISWAP) have primarily operated in Borno, frequently targeting both security personnel and civilians, resulting in the deaths and displacement of tens of thousands.

The recent attack occurred on Friday when ISWAP fighters arrived in gun trucks and launched an assault on the army’s 149 Battalion in Malam-Fatori, a town that serves as a gateway to the border with Niger, as confirmed by two soldiers and local residents. One soldier who survived the encounter recounted to Reuters via phone that the troops were caught off guard as the militants “rained bullets everywhere.”

“We made significant efforts to fend off the attackers, but after more than three hours of intense gunfire, they overwhelmed us, resulting in the death of our commanding officer, a lieutenant colonel,” the soldier stated, requesting anonymity due to restrictions on speaking to the media.

He reported that 20 soldiers were killed and several others sustained injuries.

A spokesperson for the Nigerian Army has not yet responded to a request for comment.