Suspected Boko Haram gunmen have stormed a town in northeast Nigeria, opened fire on police and civilians and killed 11 people. The attack happened late Thursday in the town of Damboa in Borno state, Boko Haram’s stronghold and where Nigeria has imposed a state of emergency as it pursues an offensive against the insurgent group. Details were slow to emerge and the area military spokesman could not be reached for comment because of a phone blackout imposed by the military, an operational measure meant to block the fighters from coordinating attacks.