Nigeria's military has launched air strikes on a Boko Haram camp, killing several Islamists, near a northeastern college campus where insurgents massacred 40 students at the weekend, a spokesman said Thursday.

"We tracked the Boko Haram terrorists to their camp in the forest outside Gujba," military spokesman in Yobe state Lazarus Eli said of the Tuesday operation.

"Fighter jets bombarded the camp while troops launched a ground offensive, which left several terrorists dead," Eli added.

On Sunday, heavily armed Boko Haram gunmen attacked an agricultural college in Gujba, killing 40 students as they slept in their dorms.

Gujba is roughly 30 kilometres (18 miles) from Yobe's capital of Damaturu.

"The whole camp was destroyed in the raid and we are on the trail of fleeing members of the terrorist group," Eli said.

The military has previously issued statements following major Boko Haram attacks, boasting of successes which are often difficult to verify.

Eli said "15 suspected terrorists" have been arrested around Gujba.

The weekend school massacre cast further doubt on the success of an ongoing military campaign, launched in May, which is aimed at crushing the four-year insurgency.

More than 100 people have been killed in a spate of school attacks since June, while dozens of others have been slaughtered in violence across the northeast, Boko Haram's historic stronghold.

The insurgents have said they are fighting to create an Islamic state in Nigeria's mainly Muslim north, but their demands have repeatedly shifted.

According to an estimate made earlier this year, the insurgency has cost more than 3,600 lives, including killings by the security forces. The current figure is likely much higher.

Nigeria is Africa's most populous country and top oil producer, roughly divided between the mainly Muslim north and a predominately Christian south.