Militants from Nigeria's Boko Haram sect attacked a prison in neighboring Niger overnight, hours before Niger's parliament was due to vote on joining a regional offensive against the militants, witnesses said. Heavy gunfire rang out as Niger's army repelled the attack, Boko Haram's third assault on the border town of Diffa in four days, residents and military sources told Reuters. Authorities ordered locals to stay in their homes and mounted roadblocks around the town by late morning. Residents said many had fled.