Witness: Twin bomb blasts kill at least 18 at mosque in northeast Nigerian city of Maiduguri

A self-defense fighter says twin bomb blasts have killed at least 18 at a northeast Nigerian mosque crowded with people observing pre-dawn prayers.

The fighter was among rescuers who evacuated bodies while troops cordoned off the zone. He spoke on condition of anonymity for fear of reprisals.

Friday's attack was the latest in a string of assaults blamed on Boko Haram Islamic extremists who have indiscriminately killed Christians and Muslims they accuse of not following their radical version of Shariah law.

The fighter said there appeared to be only one suicide bomber though "we all heard two explosions" around 5 a.m. in a mosque in the Jiddari Polo area of Maiduguri, the biggest city in the northeast and birthplace of Boko Haram.

Suicide bombers have killed hundreds in recent months.