At least 50 people were killed Tuesday in a suicide bombing in a Nigerian mosque, Reuters reports. A police spokesman in Adamawa state, Abubakar Othman, said he expected the death toll to climb because many others were seriously injured. The attack marks the largest mass killing this year in the region, where Boko Haram fighters have led a violent insurgency. Last December, two schoolgirl suicide bombers attacked a crowded market in Adamawa, killing 56 people.