As per details, at least five policemen and two passers-by were among those killed, while 16 others including eight police officials were also injured.
The explosion occurred near GPO Chowk in the vicinity of the Balochistan Assembly. The road also leads to the Chief Minister's Secretariat.
A large number of security personnel had been present near the site of the blast as a session of the Balochistan Assembly attended by almost all its members had just concluded. The area also houses several important government buildings, and is usually well secured.
According to a foreign news agency, the banned Tehreek-i-Taliban Pakistan (TTP) claimed responsibility for the attack, saying a suicide bomber targeted a police contingent returning from duty at the provincial assembly building.
The area was cordoned off and media was stopped from moving near the blast site.