Nigeria's military says 14 military and police personnel have been killed in an ambush by Boko Haram extremists.

An army statement says the security forces were on escort duty when they were attacked on Monday just outside Damaturu town in Yobe state in the north of the country.

The statement signed by army spokesman Col. Onyema Nwachukwu says efforts to pursue and "eliminate" the Boko Haram extremists are ongoing.

Nigeria's military has been fighting Boko Haram's Islamic insurgency for nearly a decade. The continued threat is a major issue for President Muhammadu Buhari as he seeks a second term in February's election.

After a recent series of deadly attacks on Nigeria's military, Buhari and others have warned that the extremists have begun using drones to as part of a resurgence.