PESHAWAR — The roof of a school collapsed in Pakistan's northwestern city of Peshawar yesterday killing 32 students mostly younger than 14, and a teacher, officials said, blaming the accident on dilapidated infrastructure.

Twenty more students were taken to hospital as residents and rescuers scrambled to pull children from under the rubble. Others in the densely populated neighbourhood described a close call.

A man who gave only his first name, Sohail, told AFP that "everyone began screaming in panic" when his niece, who had escaped the building, arrived home to tell them it had collapsed.

"When I arrived at the scene, I saw around 10 to 15 children trapped beneath the rubble, with debris piled up to their necks. We quickly pulled them out," he said.

Asim Khan of Peshawar's Lady Reading Hospital said the death toll had risen to 33 by Thursday evening, with most of the victims aged between four and 14, and a female teacher.

Most of the children who were brought to the hospital have been discharged. Three children who sustained head injuries have been admitted, Khan said.

A spokesman for the emergency rescue service in Khyber Pakhtunkhwa province said schoolchildren were crushed and trapped after the roof gave way.

"When the Rescue 1122 emergency response teams arrived at the scene, they found that one roof had collapsed onto another, causing the classroom below to be crushed and trapping children inside," spokesman Bilal Ahmad Faizi said.

AFP journalists saw dozens of people at the scene.

Images released by the emergency services showed rescue workers in high-visibility vests scrambling to move debris, rubble and dirt.

A senior official in Peshawar told AFP that initial reports suggested the roof collapse was due to "weak infrastructure".

"The school owner has been detained," the official said on condition of anonymity because he was not authorised to talk to the media.