At least 13 people were killed and five others were injured in a sectarian-motivated attack in Pakistan's southwest city of Quetta on Saturday morning, said hospital sources.

According to Xinhua sources and local media reports, the attack took place at about 08:00 a.m. local time when two unknown gunmen riding a motorcycle opened fired indiscriminately at a passenger pick-up carrying people from Hazara Shia community on their way for work near a bus stop on the Spini road in a densely populated area of the city.

The gunmen escaped after the firing. Police have arrived at the area shortly after the firing was reported and the area has been cordoned off for search operation. All the injured people have been shifted to the Bolan Medical Complex in the city.

No group has taken credit for the attack yet.

Saturday morning's incident is the second of its kind in the city over the last 12 hours or so. Late on Friday night, seven Shia devotees were reportedly shot dead in Quetta while they were heading to Iran to visit religious places.

The banned extremist group "Lashkar-e-Jhangvi" had claimed responsibility for the Friday's attack on the Shia devotees.

A spokesman of the group Ali Sher Haidri said that it was the revenge of the murder of a Sunni scholar Maulvi Karim who was killed in Quetta in firing on Thursday.

Quetta, a capital city of the insurgency-hit Balochistan province bordering Iran and Afghanistan to its west, has seen a series of bomb blasts, sectarian and target killings in recent weeks.

Also on Friday, two people including a nephew of Balochistan's Chief Minister were killed and nearly 30 others were injured in a bomb attack which occurred outside a football stadium in Mastung, a district located some 60 km south of Quetta.