The gunmen who attacked Tuesday were riding on motorbikes and stopped a bus carrying mostly Shiias who were headed to work at a vegetable market on the outskirts of Quetta, the capital of Baluchistan province, said police official Hamid Shakeel.

The gunmen forced them to stand in a line and then opened fire, killing 12 people and wounding seven others.

The dead/injured were rushed to Combined Military Hospital (CMH) and Bolan Medical Complex for the emergency treatment facilities, said reports.

The attackers made their escape before the police could arrive at the scene and cordoned off the areas including Akhtarabad, Mengalabad and surroundings.

Later, some enraged people set the ill-fated bus on fire.

The Quetta democratic Party highly condemned the attack and call for protest against the incident.

A large number of people gathered in and around the BMC hospital where they raised slogans against the attackers and they demanded maintenance of peace in Balochistan particularly in Quetta.

Later, the wounded were referred to Combined Military Hospital Quetta.

Police and hospital sources told APP that the dead were identified as Zakir, Fida Hussain, Haji Malang Achakzai, Zaki, Muhammad Ali, Qurban Ali, Ali, Jan Ali, Hussain Bakhsh and Noorullah. The injured include Ali Baba, Ashique Ali, Ayazullah, Abdullah, Muhammad Juma, Misbahulla and Abdullah.

The incident caused panic amongst citizens. The protesters torched the bus which was attacked. Girl students of Government Girls Degree College staged demonstration against the attack.

Tahafazz Azadari Council announced to mark three-day mourns.

Law enforcement agencies including Frontier Corps, police and Balochistan Constabulary have launched crackdown in many areas including Killi Akhtarabad and others and arrested about 15 suspects so far.

Talking to media persons at the hospital, Commissioner Quetta Division Naseem Lehri said that the assailants ambushed the bus and they did not came from road side. He,said that law enforcement agencies had cordoned off the entire area and they would succeed in arresting the attackers.

Governor Balochistan Nawab Zulfiqar Magsi and Chief Minister Balochistan Nawab Aslam Raisani have strongly condemned the firing incident and directed that the government would incur medical expenditures of treatment of injured persons.

Meanwhile, Home Minister Balochistan Mir Zafrullah Zehri has called an emergency meeting to review the incident.

It was also learnt that some officials of Shalkot police station have been sacked.

Further investigation into the incident was underway.