The security officials confirmed that the Balochistan Awami Party (BAP) candidate Nawabzada Siraj Raisani was among those killed in the blast.
Deputy Commissioner (DC) Qaim Lashari confirmed the casualties toll and said the incident took place during a gathering in Darengarh area of Mastung.
No individual or group has so far claimed responsibility behind the deadly blast.
This comes as at least thirty six people were killed or wounded in an explosion in Khyber Pakhtunkhwa province of Pakistan earlier today.
The incident took place in Bannu area of the province targeting the vehicle of the former chief minister and Jamiat Ulema Islam Fazal candidate Akram Khan Durrani.
District Police Officer Bannu Khurram Rashid has said the incident took place as Durrani was returning from an election rally and explosives were detonated close to his vehicle with the help of remote control.