MOGADISHU, Somalia—A car bomb exploded Wednesday outside the international airport in Somalia’s capital, Mogadishu, killing at least eight people and wounding nine others, a local doctor said. The al-Shabab extremist group claimed responsibility for the attack, saying it was targeting “white officials” passing by. Dr. Abdulkadir Adam with the Medina hospital told The Associated Press about the death toll. Witnesses at the scene said a passing U.N. convoy appeared to be the target in the blast near a checkpoint leading to the heavily fortified airport, but the U.N. mission said there were no U.N. personnel or contractors in the convoy. The al-Qaida-linked al-Shabab extremist group, which controls parts of Somalia, said via its Radio Andalus that a convoy of “white officials” had been the target. The extremist group often carries out bombings at high-profile locations in the capital. Mogadishu’s deputy mayor, Ali Abdi Wardhere, told reporters at the scene that …