The Army on Thursday released details of a three-day operation in the Mastung area of Balochistan earlier this month, in which security forces had killed 12 "hardcore terrorists, including two suicide bombers".

"The suicide bomber used against Deputy Chairman of Senate Maulana Abdul Ghafoor Haidri on May 12 was also sent by [the group targeted]," the ISPR revealed.

Inter-Services Public Relations (ISPR) said the operation was carried out on credible reports of the presence of a banned outfit's personnel who had been making contact with the militant Islamic State (IS) group.

"The operation, carried out from June 1 to 3, successfully denied the establishment of any direct or indirect IS-organised infrastructure in Pakistan," the ISPR said, adding that the killed terrorists had belonged to the banned Lashkar-i-Jhangvi Al-Almi (LeJA).

The terrorists had been operating from caves near the Isplingi (Koh-i-Siah/Koh-i- Maran) area, some 36 kilometres southeast of Mastung.

"Operation for physical clearance of target area, spread over 10km, started early morning on June 1 by [the] landing of [a] heliborne force," read the statement.

"Terrorists who were hiding in the caves offered stiff resistance. 250-metre-long gorge with steep heights and multiple caves made the clearance operation difficult and challenging.

"Intelligence and Security Forces personnel fought valiantly to clear the hideout by 3rd June," the Army said.

During the operation, five security forces personnel, including two officers, had been injured.

The ISPR statement further said that security forces destroyed an explosives facility inside the cave and recovered a cache of arms and ammunition, including 50 kilogrammes of explosives, three suicide jackets, 18 grenades, six rocket launchers, four light machine guns,18 small machine guns, four sniper rifles, 38 communication sets and ammunition of various types.