Indonesian rescue workers are racing against time to find dozens of students still trapped under the rubble of a collapsed Islamic boarding school in East Java, as the death toll from the disaster rose to six on Wednesday.

The century-old Al Khoziny school building in Sidoarjo collapsed during afternoon prayers on Monday, crushing hundreds of students inside a prayer hall. Most of the victims were boys aged between 12 and 18, while female students, praying in a separate section, managed to escape.

At least five students have been rescued after teams dug tunnels through the debris, while oxygen, food, and water have been delivered through small gaps to others believed alive but still trapped. On Wednesday afternoon, one boy was pulled out alive and taken to hospital.

Authorities said more than 100 people were injured, with over two dozen still hospitalized, many with head injuries and broken bones.

Rescue efforts have been complicated by unstable concrete slabs and steel bars, forcing workers to dig manually rather than use heavy machinery. More than 300 personnel, supported by thermal drones and detectors, are continuing the search.

Officials said the collapse occurred while two additional floors were being illegally added to the two-story prayer hall. Investigators believe the old foundation was too weak to support the new concrete structure, leading to the tragedy.

Search operations remain focused on saving those still trapped within the “golden hours,” officials added.