A madrassa (seminary) caught fire allegedly after explosives went off in the Eastern Bypass of Quetta on Sunday, a local newspaper reported.
Four rooms of the seminary and a nearby house were completely destroyed in the bombing.
According to witnesses, three injured were rescued by the students before police reached there. A search operation was launched to find the injured, but to no avail.
Operations Wing Deputy Inspector General Police (DIG) Muhammed Jafar said religious literature and explosives were seized from the wreckage. He said those in the seminary were preparing explosives that went off prematurely.
Separately, security forces foiled a sabotage bid and recovered explosives in Dera Bugti town area of Balochistan on Sunday.
According to police, acting on a tip off, Security forces along with the Bomb Disposal Squad team reached the site and defused 5 kg of explosives. It was planted beside the road by unknown men for sabotage.
Security forces cordoned off the entire area and started efforts to arrest outlaws.
Meanwhile, a man was injured by unidentified men in Nasirabad District.
According to police, the victim identified as Sabghatullah was on his way home when the assailants opened fire on him and fled from the scene.
The injured was shifted to a nearby hospital and was later referred to a Jacobabad hospital.
The reason of attack could not be ascertained so far.
