The incident occurred in the Sariab Mill area on the Quetta-Sibbi Road, Dawn reported.
Also Wednesday, a roadside bombing near a tribal area along the border with Afghanistan killed two troops.
Later Tuesday, Bugti said a police inspector was killed by gunmen in a separate attack several kilometres away.
"The people and government of Balochistan will not be deterred from the fight against terrorism", Zehri said, adding the fight will continue till the last terrorist remains.
Abdul Salam was shot multiple times, police said. PM Abbasi expressed deep grief and sorrow over the loss of precious lives during the terrorist attack.
"We have sent teams to the site to help the victims", he said. Balochistan has faced many such attacks in recent months, with security personnel in the province often being targeted in roadside explosions and suicide attacks.
Home Minister Bugti, while condemning the attack, said the war against terrorism was not over and would go on until no terrorist remained in the area.
"These cowardly attacks will not hinder our security forces in executing their duties", he added.
Talking to media following an explosion on the Sibi road Home Minister said that they are in the state of war and Pakistan is fighting with bravery the war against militants and Inshallah we will emerge victorious.
Fifteen people, including eight soldiers, were killed when a suicide bomber targeted a military truck near the Pishin bus stop in Quetta on August 13.