Government troops killed 81 Boko Haram militants in recent clearance operations in northeast Nigeria, the military said on Monday.

The operations covered "many villages" in the vast Sambisa Forest in the northeastern state of Borno, said Farouk Yahaya, theater commander of Operation Lafiya Dole.

He did not say when the operations were conducted or how long they lasted.

"The relentless troops destroyed the terrorists' camps and recovered gun trucks and weapons as the air force aircraft continue to provide close air and interdiction support to the ground forces," Yahaya said.

During the operations, he said, one soldier was killed and four others wounded in an incident involving improvised explosive devices planted by Boko Haram militants.

Boko Haram has been trying to establish an Islamist state in northeastern Nigeria since 2009. The terror group has also extended its attacks to other countries in the Lake Chad Basin.