Sunni Muslim extremists have opened fire on Shiite Muslims traveling through south-western Pakistan, killing 13 people and injuring seven others in the latest sectarian attack to hit the country, police said

Sunni militants with ideological and operational links to al Qaida and the Taliban have carried out scores of bombings and shootings against minority Shiites over the years, but recent times have been particularly bloody. The gunmen who carried out the latest attack were riding motorbikes and stopped a bus carrying mostly Shiite Muslims who were heading for work at a vegetable market on the outskirts of Quetta, the capital of Baluchistan province, said police official Hamid Shakeel. They forced people off the bus, made them stand in a line and then opened fire, he said. The dead included 12 Shiites and one Sunni, he said. Seven people were wounded - five Shiites and two Sunnis. Shiites blocked the main highway on the outskirts of Quetta to protest at the killings and set fire to the bus which took the dead and wounded to the hospital. Sunni extremists carried out a similar attack on Shiite pilgrims traveling through Baluchistan recently, killing 26 people. Pakistan is a majority Sunni Muslim state, with around 15% Shiite. In the 1980s and 1990s, Pakistan became the scene of a proxy war between mostly Shiite Iran and Sunni Saudi Arabia, with both sides funneling money to sectarian groups which regularly targeted each other. In recent years, Sunni attacks on Shiites have been far more common.