At least eight students have died and 136 others were hurt after a bomb blast ripped through an Islamic seminary on the outskirts of the north-west Pakistani city of Peshawar.
The bombing happened as a prominent religious scholar was delivering a lecture about the teachings of Islam at the main hall of the Jamia Zubairia madrassa, a police spokesman said.
He added that initial investigations suggest the bomb went off minutes after someone left a bag at the madrassa.
Several of the injured students are in critical condition, and hospital authorities fear the death toll could climb further.
Authorities said some seminary teachers and employees were also wounded in the bombing.
Initially, police said the bombing killed and wounded children studying at the seminary, but later revised their account to say that the students were in their mid-20s.
Shortly after the attack, residents rushed to the seminary to check up on their sons or relatives who were studying there.
Some Afghan students studying at the seminary were also among the wounded, officials said.
Prime Minister Imran Khan condemned the bombing. “I want to assure my nation we will ensure the terrorists responsible for this cowardly barbaric attack are brought to justice,” he said.
The bombing drew condemnation from the country’s opposition party, which has been holding rallies intended to put pressure on Mr Khan’s government to quit.
Another witness, Saeed Ullah, 24, said up to 500 students were present at the seminary’s main hall at the time of the explosion. He said teachers were also among those who were injured in the bombing.
A video filmed by a student at the scene showed the Islamic scholar Mr Haqqani delivering a lecture when the bomb exploded. It was unclear whether the teacher was among the wounded.
The attack comes days after Pakistani intelligence warned that militants could target public places and important buildings, including seminaries and mosques across Pakistan, including Peshawar.
No-one has claimed responsibility for the attack in Peshawar, the provincial capital of Pakistan’s Khyber Pakhtunkhwa province bordering Afghanistan.
The province has been the scene of such militant attacks in recent years, but sectarian violence has also killed or wounded people at mosques or seminaries across Pakistan.
The latest attack comes two days after a bombing in the south-western city of Quetta killed three people.
Mohammad Khurasani, a spokesman for the Pakistani Taliban, condemned the bombing. In a statement, he described the attack as a cowardly act, claiming that the country’s institutions were behind it.