LAGOS, Nigeria (AP) — At least 51 civilians have been killed in Nigeria’s unrest following days of peaceful protests over police abuses, the president said Friday, blaming “hooliganism” for the violence while asserting that security forces have used “extreme restraint.” President Muhammadu Buhari’s comments are expected to further inflame tensions in Africa’s most populous country after Amnesty International reported that soldiers shot and killed at least 12 demonstrators Tuesday night as a large crowd sang the national anthem. The deaths sparked international condemnation. In a statement, Buhari also said 11 policemen and seven soldiers had been killed by “rioters” as of Thursday, and “the mayhem has not stopped.” He said another 37 civilians were injured in some of Nigeria’s worst turmoil in years.