Boko Haram leader Abubakar Shekau in a new video is vowing to continue his insurgency until he establishes an Islamic caliphate across West and Central Africa.

In the 27-minute video seen by The Associated Press, Shekau says his fighters will continue to attack Nigeria's northeastern city of Maiduguri with suicide bombers until the country accepts the ways of Islam and jettisons constitutional rule.

Shekau also denies neighboring Cameroon's claims earlier this month that 60 of his men were killed and 5,000 people were rescued from captivity.

A multinational force has been fighting Nigeria's homegrown Boko Haram extremists in the Lake Chad region amid one of Africa's largest humanitarian crises.

Nigeria's military has claimed on a number of occasions to have killed Shekau.