Three children were killed, and three people were injured on Wednesday when a landmine exploded inside a house in Sanni, a tehsil of Bolan district, police said.
Acting SP Kachhi Jan Muhammad Khosa said the blast occurred in the home of a man identified as Abdul Hai Jatoi.
The explosion was so powerful that the roof collapsed and the walls caved in while family members were inside.
According to police, two boys and a girl died on the spot, while a girl and two men were injured.
The deceased were identified as 14-year-old Nadeem Ahmed, 13-year-old Sona Khan and 13-14-year-old Bibi Bakhtawar.
The injured were shifted to a nearby hospital for treatment.
Initial findings suggest unknown armed individuals planted explosive material inside the house two nights earlier, which detonated on Wednesday.
Police said the nature of the incident indicates it was a targeted attack.
Security forces and a bomb disposal squad reached the site soon after the blast and cordoned off the area.
A search operation has been launched to trace the perpetrators.
SP Khosa said an FIR has been registered and an investigation is underway, with sensitive agencies also assisting.