A blast targeting Pakistani forces in the Zarkho area of Daghari in Quetta caused casualties on Thursday, local sources said.
The explosion occurred when army personnel on foot reached the site of a new post under construction, the sources said.
Pakistani forces cordoned off the area and restricted movement after the blast, the sources added.
The number of casualties could not be independently confirmed.
A day earlier, an explosion killed at least three Pakistani bomb disposal personnel in the Manguchar area of Kalat district while they were attempting to defuse an explosive device.
No group has claimed responsibility for either incident, and there was no immediate comment from Pakistani authorities.