KANO - Gunmen have attacked two more police stations in Nigeria's second city of Kano, killing at least two people amid a wave of escalating violence blamed on Islamists. One of the attacks occurred at dawn on Monday, setting off a gun battle with police, residents said. On Sunday night, gunmen stormed another police station near a bus station, leaving two civilians dead. It was not immediately clear who was behind the violence, but Kano, the main northern city in Nigeria, has been targeted in recent weeks by attacks claimed by Islamist group Boko Haram. The violence has included coordinated bombings and shootings on January 20.