BOLAN(National times)- A powerful explosion inside a house in Bolan, a city in Balochistan province, killed at least three children and wounded three other persons, Dunya News reported on Wednesday. According to police, the blast was so severe that the roof and walls of the house caved-in. Police said that the deceased were identified as 14-year-old Nadeem Ahmed, 13-year-old Sona Khan and 13-year-old Bibi Bakhtawar. The injured persons were shifted to hospital in critical condition. According to police officials, initial investigations indicate that some unidentified persons planted explosive material in the house two nights earlier, which detonated today. The nature of the incident suggests it was a targeted explosion. Sources said that as soon as information about the blast was received, security forces and the bomb disposal squad reached the spot. The forces cordoned off the entire area, and a search operation has been launched to find the culprits.