The high intensity blast occurred in a parking lot near Pishin bus stop which is in a high security area in the provincial capital Quetta.
According to an Inter-Services Public Relations (ISPR) statement, the army truck which was patrolling the area had been targeted and eight soldiers were killed in the attack.
Pakistan army chief General Javed Qamar Bajwa has condemned the "cowardly" attack meant to disrupt Independence day celebrations, the statement said, adding the attack would not deter the determination of the army to fight terrorism.
The injured also included around 10 soldiers who were in the truck. Pakistan army has now taken control of the affected area, it said.
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Balochistan's Home Minister Mir Sarfaraz Bugti said there were seven civilians among those killed in the blast.
"The bomb disposal squad has reached the spot and we will be able to confirm soon whether it was a suicide attack or a planted bomb," he said.
Bugti said around 30 injured persons were shifted to the Civil hospital for treatment and admitted that the condition of six to seven people was critical.
The blast was so loud that it was heard in far off areas and caused a huge fire in which some vehicles and auto rickshaws were also damaged.
An official of the Edhi trust in Quetta said around 15 bodies were shifted before adding that the death toll could be much higher.
"The explosion was very powerful and loud. Its intensity was severe. Several car and auto rickshaws have been burnt or damaged after the blast as they caught fire due to the intensity of the blast," the official said.
Quetta is the capital city of the restive Balochistan province. Balochistan has oil and gas resources but has witnessed several terrorist attacks recently by militants and separatists while banned outfits have also carried out sectarian killings in the province.