A spokesman for the Frontier Corps, Khan Wasey said so far 13 militants were killed in the operation in the Kalat and Mastung districts of the province.
"Security Forces have killed 13 militants since yesterday," he said in a statement issued this afternoon.
Wasey said that six other militants were injured while a dozen were also rounded up during the operation.
He said the militants including a commander were killed during clashes with security forces and they belonged to a banned militant organisation, involved in a series of terrorist activities in the area.
The forces were backed by helicopter during the operation.
The Baluchistan province rich in natural resources and gas has been hit by a spate of separatist and sectarian violence in recent years while militants of banned outfits have also carried out attacks on security forces and installations.