A powerful blast ripped through a madarsa in Peshawar on Tuesday, killing at least eight people, mostly students, and wounding over 120, senior police officials said.

The blast occurred at around 8:30am at a local mosque, which also serves as a madarsa in Dir Colony. At the time of the blast, students were reading the Quran, Peshawar police chief Muhammad Ali Khan said.

Khyber Pakhtunkhwa chief minister’s adviser on information Kamran Bangash and spokesman of the LRH Hospital Asim Khan confirmed that eight persons have died and 124 were injured.

“Those who spread terror will never succeed in their mission,” Bangash said, adding that the incident would be fully probed and the perpetrators will be brought to book. There was no immediate claim of responsibility for the blast. Peshawar is near the border with Afghanistan.

A bag filled with explosives was kept close to wall of the madarsa by an unknown person, the Peshawar superintendent of police, Waqar Azeem said. He added that the bag is believed to have had an IED device.

An official from the Counter Terrorism Department (CTD) said 4 to 5kg of explosives was used in the blast.

Most of the students who died and were injured were aged between 7 and 11 years, the official said, adding that many of them were from Afghanistan.

Prime Minister Imran Khan condemned the blast and prayed for the speedy recovery of the injured.

“Deeply saddened by terrorist attack on madrassah in Peshawar. My condolences go to the victims families & prayers for early recovery of the injured. I want to assure my nation we will ensure the terrorists responsible for this cowardly barbaric attack are brought to justice asap,” he tweeted.

There was a general threat alert in the Peshawar district, said Khyber Pakhtunkhwa police chief Sanaullah Abbasi, who also confirmed the death toll. According to the police, around 40-50 students were present inside the madarsa when the bomb went off. The madarsa’s administration said around 1,100 students study at the institution.

Khyber Pakhtunkhwa chief minister Mehmud Khan condemned the attack.