Boko Haram, which has sought to trade hostages in return for its own members detained by the security forces, has been accused of regular attacks, despite a military state of emergency in the region.

On Monday, at least eight people were killed and 20 others wounded by an explosion on a college campus in Kano, northern Nigeria. It was not immediately known whether the attack was part of Boko Haram’s campaign to promote an Islamic state.

Earlier this month, the group killed scores of people — possibly hundreds, according to the Nigerian news media — in what local officials described as a massacre in northeastern Nigeria along the border with Cameroon, which has deployed thousands of its troops as part of a regional campaign against the group.