Quetta Police Chief Abdul Razzaq Cheema said the February 17 rally was being staged by dozens of Sunni Muslim followers of the radical Ahle Sunnat Wal Jammat (ASWJ) party.
The ASWJ is considered the political entity of the Lashkar-e Jhangvi — an extremist faction that has claimed responsibility for numerous deadly attacks against Pakistan’s Shi’a minority.
There was no immediate claim of responsibility for the February 17 bombing.
Baluch separatists as well as rival Shi’ite and Sunni militant groups operate in the province and have staged similar attacks in the past.
Hospital officials in Quetta say some of the injured people were listed in critical condition.
Cheema told RFE/RL victims killed in the blast included three police officers and four civilians.
Quetta Civil Hospital spokesman Waseem Baig put the number of those wounded at 19. Cheema said the blast occurred as a protest was under way in front of the Quetta Press Club.
A police official told RFE/RL’s Radio Mashaal that the suicide bomber was riding a motorcycle and detonated his explosives when he was stopped by authorities as he approached the demonstration.
The blast also damaged several vehicles parked nearby.