The shootings occurred on Saturday outside two polling stations over allegations of vote rigging during a by-election, said Mir Ahmed Nausherwani, a government administrator in the district of Qilla Abdullah, where the violence occurred.
Two people were killed and seven wounded in the first clash in the village of Killi Gul Khan. Another was killed and five wounded in a second exchange of gunfire in the nearby village of Killi Khwaja Noor, Nausherwani said.
The violence occurred between supporters of a candidate from the ruling Pakistan Muslim League-Q party and his rival from the ethnic-based Pashtoonkhwa Milli Awami Party.
Nausherwani said authorities would investigate who was responsible for initiating the clashes. Three people were arrested, but it wasn't clear which group they were from.
The by-election in Qilla Abdullah was held after a lawmaker from the constituency was disqualified by the Supreme Court.