The troops were escorting employees of a state-run oil and gas company on Monday when their vehicle, the last in an eight-car convoy, was hit by a landmine explosion set off by remote control, said Abd al-Rauf, home secretary of the province of Baluchistan.
The attack, apparently targeted at workers from Pakistan Petroleum, took place near the town of Sui, 280km southeast of Quetta, the provincial capital.
In a separate attack, one paramilitary guard was killed and one wounded on Sunday, when unidentified men fired at a convoy of employees of the same company, which operates the largest natural gas field in the country.
Four local residents were also wounded on Sunday when suspected tribesmen fired 20 rockets at a camp once used by Chinese workers in the same region, a local government official said.
Police in the town of Kalat, about 140km south of Quetta, said their police station was hit by a locally-made bomb early on Sunday morning. It caused only minor damage to the building and no one was hurt.
Baluchistan, one of Pakistan's poorest provinces, has suffered a spate of attacks on paramilitary troops and state-owned oil and gas installations by suspected tribesmen fighting for a share of benefits from exploration.
Officials say violence there is not connected with an ongoing military campaign against al-Qaida-linked fighters in the semi-autonomous western tribal regions of Pakistan.