Members of Hazara Shia community were heading to work in a pick-up vehicle, when they came under attack near a bus stop on Spini road of Quetta, the capital of Balochistan province, witnesses said.
According to media reports, a woman was among 11 people killed in the incident that also left four others injured. The attack came a day after seven Shia devotees, who were heading to Iran to visit religious places, were killed by gunmen in Quetta.
The banned extremist group ''Lashkar-e-Jhangvi'' claimed responsibility for Friday's attack.
A spokesman for the group, who was identified as Ali Sher Haidri, said the attack was in retaliation for the murder of Sunni scholar Maulvi Karim, who was killed in Quetta in a firing incident on Thursday.
Quetta has seen a series of bomb blasts and sectarian and targeted attacks in recent weeks. The majority of Pakistanis are Sunni Muslims, with Shiites accounting for around 15 per cent of the country's population of over 170 million.
Also yesterday, a close relative of Balochistan's Chief Minister and another person were killed in a bomb attack in Mastung district near Quetta. The bomb attack that took place outside a football stadium also left nearly 30 people injured, police said.
Nawabzada Mir Akmal Raisanai, nephew of Balochistan Chief Minister Nawabzada Aslam Raisani, succumbed to his injuries in a military hospital in Quetta.