Balochistan Home Minister Sarfaraz Bugti while condemning the attack confirmed the deaths in the attack.
The minister informed that six policemen were killed and 22 were injured in the blast.
In a separate incident, Police Inspector Abdul Salam was shot dead on Quetta's Qambrani Road, in what security sources claim was a targeted killing. Balochistan has faced many such attacks in recent months, with security personnel in the province often being targeted in roadside explosions and suicide attacks.
Reportedly, the exploded truck was carrying police recruits.
Police and FC troops have reached the area, which has been cordoned off for gathering evidence. "Our Mujahideen did it", said Mohamed Khorasani, a spokesman for the group.
He said the bodies were badly burnt, adding that two critically injured victims had been shifted to BMC's burn ward.
"These cowardly attacks can not shake our unflinching national resolve against terrorism and extremism", the prime minister said in a statement.More news: Sensex, Nifty touch record high
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The Tehreek-i-Taliban Pakistan claimed responsibility for the attack.
Home Minister Bugti said that Indian and Afghanistan spy agencies may be behind the attack as they have perpetrated such attacks in the past.
"The war against terrorism is not over". He said the bomb was so powerful that they could find only the engine of the vehicle used in the blast. He further said that a forensic team from Lahore would arrive in Quetta tomorrow (Thursday) to aid in the probe.
Following the blast, Chief Minister Nawab Sanaullah Zehri chaired an emergency meeting on law and order situation which was attended by provincial ministers, Chief Secretary, IGP and DIG.
He prayed for the eternal peace of departed souls and grant of courage to the families to bear this irreparable loss and also directed best medical treatment for the injured and prayed for their swift recovery.
Members of the minority Shia community and security forces are frequently attacked by militants in the province. At least 14 people, including seven police personnel, were killed and 21 injured this year in June in a suicide auto bombing near the office of provincial police chief of Balochistan.
He added that an investigation was under way to determine whether it was a suicide bombing or the explosives-laden vehicle was detonated remotely.