In the first incident, gunmen fired indiscriminately at men working in a scrap market on Sarki Road in Quetta, the capital of Balochistan province.
Four Shia Hazaras were killed instantly, local residents and a Shia organisation said.
The gunmen, who were riding a motorcycle, escaped before police cordoned off the area and launched a search.
No group claimed responsibility for the attack though such incidents are usually blamed on the banned Lashkar-e-Jhangvi, a notorious sectarian group.
A member of a polio team was shot and killed by gunmen in Rind Garh area of Quetta, police said.
Gunmen riding a motorcycle fired at the team while it was administering anti-polio drops to children.
One member of the team was hit by bullets and died while being taken to hospital.
Police officials said personal enmity could have been the cause of the attack.
