According to police, the blast took place when a vehicle of security forces was on a patrol duty at Karachi-Quetta National Highway.
The security personnel remained safe from the attack and no casualties were reported.
Police said that the explosive were planted in a vegetable cart.
Heavy contingents of Police and Frontier Corps (FC) arrived at the scene and surrounded the area.
According to Bomb Disposal Squad (BDS), six to eight kilograms of explosives were used in the blast.