At least 50 people were killed on Tuesday in a suicide bombing that targeted worshipers at a mosque in Nigeria, said police, A teenage bomber detonated as the worshipers gathered for morning prayers at a mosque in the northeastern Adamawa state town of Mubi, in one of the regions deadliest attacks in years. Police spokesman Othman Abubakar told The Associated Press they were "still trying to ascertain the number of injured because they are in various hospitals." He said the young man detonated his explosives while mingling among the worshipers. While there was no immediate claim of responsibility for the bombing in Mubi, suspicion immediately fell on the Boko Haram extremist group. The group is based in neighboring Borno state and has been blamed for scores of similar attacks over the years. Boko Haram increasingly has been using teenagers or young women as bombers, many of whom have been abducted. It typically mounts suicide attacks in crowded public places such as mosques and markets. Tuesday’s attack is the highest loss of life since 56 people were killed in the same state last December, when two schoolgirl suicide bombers killed 56 people and wounded dozens more in a coordinated attack on a crowded market. While Nigerias military in recent months has flushed Boko Haram from its forest stronghold, President Muhammadu Buharis claim late last year that the extremist group had been "crushed" has proven to be premature. Most attacks by the group focus on Borno state, the birthplace of the insurgency. The group held a swathe of land around the size of Belgium in Borno, Adamawa and Yobe states until early 2015 but were forced out by Nigeria’s army backed by troops from neighboring countries. Boko Haram has been blamed for more than 20,000 deaths during its nearly decade-old insurgency, which has spilled over into neighboring countries and displaced millions of people, creating a vast humanitarian crisis.