Self-defense fighters say they fought alongside Nigerian soldiers to kill 150 Boko Haram militants and rescue 36 child and women captives of the Islamic uprising in the country's northeast.

Jubilant civilians who participated in Tuesday night's assault said they went to the Madagali and Gwoza areas acting on intelligence that the extremists were planning a large attack.

Self-defense fighter Bukar Jimeta said they killed at least 150 militants and recovered guns and explosives used in suicide bombings that have killed hundreds in recent months.

Civilian hunter Young Morris said they rescued 36 kidnapped children and women.

Nigeria's military has been promising a final onslaught against the militants whose six-year uprising has killed 20,000 people. On Tuesday, they called for insurgents to surrender. Boko Haram denies scores of extremists have surrendered.