Gunmen stormed a mosque in northeastern Nigeria on Sunday and killed 44 worshipers, a day after 12 people were shot dead in a nearby village, officials said Monday. The weekend attacks were believed to have been acts of vengeance against citizens who cooperated with the military in its campaign against the Islamist extremist group Boko Haram, a senior government official said. Gunmen believed to be Boko Haram members attacked the mosque in Konduga, 22 miles outside Maiduguri, the capital of Nigeria’s Borno State, the official said. Gunmen also suspected of being Boko Haram members attacked the nearby village of Ngom and killed 12 people on Saturday night, a local official said. Some Konduga residents said the attackers wore army uniforms, a tactic gunmen have used in the past to disguise themselves.