The incident took place Saturday near the provincial capital, Quetta.
A police official says gunmen on motorcycles stopped a bus and shot dead five of the passengers, then killed two other Shi'ites in the same area.
Baluchistan is home to pro-Taliban factions and other militant groups including Baluch separatists, who have been fighting for political autonomy and a greater share of the profits from the region's natural resources.
Earlier Saturday, a U.S. drone strike killed at least four suspected militants in Pakistan's restive tribal region, near the Afghan border.
Security officials say the drones fired at least four missiles at a house in the Degan area of North Waziristan, a known stronghold of al-Qaida and the Taliban.
Authorities say the targeted area is dominated by the Hafiz Gul Bahadur militant group.
Drone strikes are a contentious issue between the U.S. and Pakistan. Pakistan says the strikes violate its sovereignty, but the Obama Administration says they are a key tool in the effort to defeat al-Qaida. VoA.