PESHAWAR, Pakistan (AP) — The roof of a private school collapsed in northwestern Pakistan on Thursday, killing at least 17 children and a teacher and injuring more than three dozen others, an emergency services official said.

Several children remained trapped under the rubble in Peshawar, the capital of Khyber Pakhtunkhwa province, said Bilal Faizi, a spokesman for the emergency services.

A hospital spokesman, Mohammad Asim, also confirmed the casualties, saying some of the injured were in critical condition.

Rescuers said that they were removing debris to reach those trapped.

In July, a roof collapsed at a tutoring center under construction in Lahore, killing four schoolchildren.

Building collapses are common in Pakistan, where construction standards are often poorly enforced. Many structures are built with substandard materials, and safety regulations are frequently ignored to reduce costs.