MAIDUGURI, Nigeria -- An Islamic extremist leader in northeastern Nigeria says the bloody insurgency will continue because Allah says they must decapitate and mutilate.

In a video newly released Saturday, Abubakar Shekau claims responsibility for the Dec. 20 attack on a tank battalion barracks and says his men would have eaten their enemies, but Allah forbids cannibalism. Witnesses said insurgents put soldiers to flight and set the complex ablaze before they were driven off by a jetfighter.

Shekau warns Christians not to go to churches in this holy month, though Christmas passed in Nigeria with none of the feared terrorist attacks. Five churches were bombed Christmas Day 2011 and dozens of people died.

The extremist leader scoffs at bounties on his head -- $7 million from the United States and $312,500 from Nigeria.