A gang of armed men killed at least 15 people at a mosque in northwest Nigeria’s Zamfara state, residents said on Saturday. The attack in the Bukkuyum local government area took place during Friday prayers at the Jumu’at central mosque in Ruwan Jema town, three residents told Reuters. “The armed bandits came on motorbikes while holding their guns and moved straight to the mosque and began to shoot sporadically us,” resident Amimu Mustapha said. Another resident who asked not to be named said the attack took place at roughly 2 p.m. local time, adding there were many others injured. A spokesman …