The blast was heard in far-flung areas of the provincial capital.
According to police the explosives were planted in a rickshaw parked at the roadside. The explosion damaged a vehicle of Frontier Corps (FC) parked nearby.
Quetta Police chief Abdul Razzaq Cheema has claimed that around 100 kilogrammes of explosives were used in the terrorist attack.
The law enforcement agencies cordoned off the area after the attack and launched a search operation. Law enforcement personnel detained 20 suspects during the search operation.
According to earlier reports six persons were injured in bomb blast in Sariab area of Quetta.
The law enforcement agencies and rescuers rushed to the crime scene and transferred six injured persons to Civil Hospital Quetta for medical attendance. The injured also included three security men.
The law enforcement agencies cordoned off the area and initiated a search operation. According to investigation officials the bomb device was detonated with remote-control.
Balochistan, Pakistan’s largest province by land mass and smallest in population, has been hotbed of an insurgency demanding the right of local population over the natural resources of the resources rich southwestern province of Pakistan.