According to eyewitnesses, a white auto parked on the roadside exploded as a truck carrying around 30 Rapid Response Force (RRF) personnel passed by.
Prime Minister Shahid Khaqan Abbasi condemned the attack along with Balochistan Chief Minister Nawab Sanaullah Khan Zehri and directed authorities to provide best medical treatment to the injured.
Rescue teams immediately rushed to the spot and shifted bodies and the injured persons to Quetta Civil Hospital.
Security forces have cordoned off the area and kicked off a search operation in the surroundings.More news: Watford players praise manager Marc Silva after victory over Arsenal
Baluchistan and Quetta in particular, are systematically attacked by several radical groups, especially by the Pakistani Taliban. According to hospital staff, the condition of seven injured was critical.
"A forensic team is reaching from Lahore and will determine whether it was a suicide bomb attack or whether explosives were detonated close to the vehicle", Bugti said. "We will continue the war against these terrorists and we will defeat them".
In Quetta's Qambarani Road, a police inspector Abdul Salam was gunned down.
"These cowardly attacks will not hinder our security forces in executing their duties", he added.More news: Jets fall to Patriots after controversial replay call
Balochistan has experienced incidents of violence and targeted killings for over a decade.
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.
The loss of precious lives in terrorist attack in #Quetta is regrettable & highly condemnable.
On August 12, at least 15 people, among them eight soldiers, were martyred and 40 others wounded when a suicide bomber targeted a military truck near the Pishin bus stop in Quetta. Earlier in June, 14 people ─ including seven policemen ─ were killed in a powerful blast in Quetta's Gulistan Road area.More news: Top Republican senator: Trump is 'castrating' Secretary of State Rex Tillerson