At least 29 Shia Muslim pilgrims have been killed after gunmen opened fire on a bus in Pakistan's southwestern province of Balochistan, Press TV reports. Officials told Press TV that the gunmen riding motorcycles attacked the bus in Mastung area on Quetta-Taftan road of southwestern Pakistan on Tuesday. About 30 other people were also injured in the shooting, according to officials. Most of the victims belonged to Hazara tribe of Shia Muslims. The bus carrying Shia pilgrims was on its way from Quetta to the Iranian border when militants targeted it. Every year millions of Muslims pilgrims flock to the holy shrines in the Iranian cities of Mashhad and Qom. Pakistani security forces reached the area and started rescue operation following the incident. The death toll is expected to rise further as most of the injured are said to be in critical conditions. No group or person has claimed responsibility for the attack. Pro-Taliban groups have launched a violent campaign against Shia Muslims, and appear to have widened their terror campaign in major Pakistani cities. Several Shia religious gatherings have been targeted in different parts of the country over the past few months. Shia sources say they make up one-third of Pakistan's population of nearly 170 million. Since the 1980s, thousands of people have been killed in sectarian-related incidents in Pakistan. Show Less >>