Al-Shabaab militants killed at least 12 people Tuesday in a car bombing and assault on a police station shared by African Union peacekeepers in a key Somali commercial hub, authorities said. At least four of the Islamist attackers also were killed as Somali police and AU troops responded to the assault on the police station in Beledweyne, about 200 miles north of the Somali capital of Mogadishu, said Abdi Farah Laqanyo, governor of the Hiran region. The attack is the latest on Somali and AU forces by Al-Shabaab, a group that is fighting the government in hopes of turning Somalia into a fundamentalist Islamic state. A car packed with explosives was driven into the station's gate and burst "into a huge ball of flames" about 11 a.m., Laqanyo said. Attackers then entered the police compound and exchanged fire with police and AU forces, authorities said. The station is a base for Djiboutian troops serving as peacekeepers for the African Union Mission in Somalia, known as AMISOM, which supports Somali forces in cracking down on Al-Shabaab.