It’s the latest unrest to hit Baluchistan province, where militants have tried to target a naval facility and a government building in recent weeks.
Nobody immediately claimed responsibility for Sunday’s blast in Khuzdar, which is on the main highway connecting the provincial capital Quetta with the port city of Karachi in neighboring Sindh province.
Deputy Commissioner Muhammad Arif Zarkon said a woman and two police officers were among the wounded.
For years, Baluchistan has been the scene of a low-level insurgency by groups demanding independence from the central government in Islamabad. Although the government says it has quelled the insurgency, violence in the province has persisted.
Last Saturday, an improvised explosive device killed one person and wounded 14, including three soldiers.