At least 27 students, most younger than 13, and a teacher lost their lives when a school roof gave way during classes in Peshawar on Thursday.
Authorities cautioned that the death count might increase as more children are thought to be buried under the rubble.
The collapse happened at the privately run Al-Khair Education Center, where rescuers retrieved blood-stained students from the debris.
District emergency officer Iftikhar Khan reported that at least 45 children had been removed, and said additional pupils were still reported trapped beneath the wreckage.
Government official Bilal Faizi stated rescue crews were working to pull bodies out and transport the injured to hospital.
Lady Reading Hospital spokesperson Mohammad Asim noted that 20 injured and most of the dead were taken to the hospital.
A rescue official explained that the ceiling fell on the pupils after the roof of an upper floor collapsed, crushing two storeys.
Authorities announced an investigation has been ordered to find the cause of the collapse.
Peshawar police chief Mian Saeed warned the death toll could rise, as only 47 of the 110 students in three classrooms had been rescued.
"It was a weak building structure. Its roof was overloaded with construction on a weak structure that caused the collapse," he said.
