The Islamic State has claimed it killed 12 Nigerian troops and others injured on Monday when its fighters attacked "a barracks of the apostate Nigerian Army" in Gajiram, Nganzai local government area of Borno State.
The terrorist group said three armored vehicles, "tanks" and four-wheel-drive vehicles were destroyed and the base was burned, and that weapons, ammunition and 4×4' vehicles were captured.
Although the spokesperson of Operation Lafiya Dole Colonel Ado Isa confirmed the attack, he, however, played down the impact of the attack.
He said that only a detailed situation report that is still being awaited will provide an insight into the true situation of things.
"Our men are now fully on the ground but details of casualty on our part and on the part of our adversaries is what we are still waiting for," Isa told Channels TV on Wednesday.
"But I assure you that our troops are there on ground in Gajiram and members of the community are there too," Isa added.
Security sources and residents told AFP on Tuesday that 15 soldiers were killed when the ISWAP faction of Boko Haram in nine armored trucks overran the base and looted nearby Gajiram town.
"They dislodged troops from the base after a fight," a security source told AFP. "We don't know the extent of damage and looting in the base. An assessment is being carried out."
Soldiers were seen returning to the town from the bush on Tuesday morning.
"Fifteen bodies of soldiers have so far been recovered in a search and rescue operation," a military officer, who asked not to be named, later told AFP. "This figure could change as the operation is still ongoing and many troops remain unaccounted" for.
Residents said the insurgents drove into the town after sacking the base and looted shops, and that some residents fled into the bush while others shut themselves in their homes.
The Gajiram attack came a day after they killed 30 people on Sunday in a triple suicide bombing in the region that also bore the hallmarks of Boko Haram.
Boko Haram's decade-long campaign of violence has killed 27,000 people and displaced about two million in Nigeria.