A gunman opened fire on a bus carrying Shiite Muslim pilgrims in southwestern Pakistan on Wednesday, killing three people and wounding nine others, police said. The shooting happened in Akhtarabad, on the outskirts of Quetta, the capital of oil and gas-rich Baluchistan province, which borders Afghanistan and Iran. \"At least three people were killed and nine others were wounded when one of the four gunmen riding two motorbikes opened fire on a bus carrying Shiite pilgrims to Iran,\" senior local police official Farid Breach told AFP. He said it appeared to have been a sectarian attack but that the shooting was under investigation. Local intelligence officials also confirmed the incident and casualties. There was no immediate claim of responsibility but Baluchistan is rife with Islamist militancy, sectarian violence between majority Sunni and minority Shiite Muslims and a regional insurgency waged by separatists. Shiite Muslims account for around a fifth of Pakistan\'s 167 million population, which is dominated by Sunni Muslims. Thousands of people have died in sectarian attacks since the late 1980s.