Two members of the security forces were also injured in the confrontation.
Officials said that the shootout broke out in the wake of a search operation by the Frontier Corps and intelligence personnel in the Dringen Nullah area in Sui tehsil.
When the suspects found themselves surrounded by security personnel, they opened fire on them, injuring two FC men. The security personnel returned fire.
The FC spokesperson said that the militants involved in the encounter belonged to the banned Baloch Republican Army. He said that a huge quantity of arms, ammunition and 400 kilogrammes of explosives, an improvised-explosive device, 40-metre-long fuse cord and 300m detonating cord were seized from the hideout, which was later demolished.
Elsewhere, the spokesperson said the FC personnel seized a local leader of the banned BLA in the Sheikhri area of Kalat. He said that two other militants were arrested from the Sami area of Turbat, while five others were taken into custody from the Buleda area.