A four-story prayer hall in an Islamic boarding school on Indonesia’s main island of Java collapsed Monday, killing at least one student and leaving dozens of others feared trapped under the rubble, officials said.

Rescue workers, police and soldiers were desperately digging through concrete debris looking for survivors in overnight rescue operations, supported by several heavy equipment.

The incident occurred when more than 100 students were performing afternoon prayers in the under-construction prayer hall at Al Khoziny Islamic boarding school in Sidoarjo, a town in East Java province, according to local police.

East Java police spokesperson Jules Abraham Abast said the sudden collapse left at least one male student dead and 79 injured, some in a critical condition.

Survivors said most of the victims are male students, as females were praying separately in another part of the building.

Residents, teachers and administrators were rushed to local hospitals with broken bones and head injuries.

Abast said the old prayer hall that originally had only two stories was renovated by adding two more floors for education purposes without a permit.

By Monday evening, rescuers were able to pull four more injured people from the debris during a gruelling search effort, and were still trying to rescue three children who are still alive but trapped under the rubble.

Nanang Sigit, who led rescue efforts, said his team was

running oxygen and water to those still trapped under the debris to keep them alive.

He added that rescue efforts were slow due to the risk of further collapse and the difficulty of penetrating the steel-reinforced concrete.

AP video by Trisnadi (one name given)