At least four security personnel and two civilians were injured in a blast in Quetta's Western Bypass area on Monday, police sources said.
The Frontier Corps (FC) personnel were on a routine patrol when their vehicle was targeted through a bomb planted on the roadside.
The blast left the vehicle partially damaged. The injured were rushed to the FC hospital.
Police and FC personnel reached the site and started investigation into the incident.
There has been no immediate claim of responsibility for the blast.
In November last year, three FC officials were killed and seven others were injured in a roadside improvised explosive device (IED) blast which occurred near their vehicle in Peshawar's Bashirabad area.
The number of attacks in the country has fallen around 70 per cent, due to a combination of the military offensive against Taliban bases along the Afghan border and government initiatives to tackle militancy, but attacks on security and civilian targets continue to occur occasionally.