SIDOARJO, Indonesia (AP) — Recovery crews on Friday pulled multiple bodies from beneath the rubble of a school that collapsed in Indonesia, with dozens of students still unaccounted for and the death toll expected to rise.

Rescuers had been initially working by hand after the building being renovated caved in Monday as they searched for survivors. But with no more signs of life detected by Thursday they turned to heavy excavators equipped with jackhammers to help them progress more rapidly.

By evening on Friday they had found five bodies, bringing the confirmed death toll to 10, with more than 50 students still unaccounted for.

The structure fell on top of hundreds of people in a prayer hall at the century-old al Khoziny Islamic boarding school in Sidoarjo on the eastern side of Indonesia's Java island.

The students were mostly boys in grades seven to 12, between the ages of 12 and 19. Female students were praying in another part of the building and managed to escape, survivors said.

Thirteen-year-old Rizalul Qoib, one of 105 survivors, returned to the scene on Friday to look at what was left of his school, and said he was lucky to have gotten out with only a minor gash to his head.

He said, like the others, he had been praying when he heard something like the sound of falling rocks, which got louder and louder.

"I stopped praying and fled when I felt the floor shaking," he recalled.

"Suddenly the building collapsed, the debris of the roof fell on my head, my face."

Then the room went dark, but he heard someone shouting "this way, this way" and he followed the voice until he eventually found a narrow gap in the rubble."

"I just followed the light," he said.

Many of the others who were injured but managed to escape or were rescued suffered serious head trauma and broken bones and are still being treated in the hospital.

Two of the bodies found Friday were in the prayer hall area and one was found closer to an exit as if he had been attempting to escape, according to Suharyanto, the head of Indonesia's National Disaster Mitigation Agency, who goes by one name as is common in Indonesia.

Authorities have said the building was two stories, but two more levels were being added without a permit. Police said the old building's foundation apparently was unable to support two floors of concrete and collapsed during the pouring process.

School officials have not yet commented.

Crews worked in the hot sun Friday to break up and remove large slabs of concrete, with the smell of decomposing bodies a grim reminder of what they would find underneath.

Suharyanto told reporters at the scene that the recovery efforts were expected to be complete by the end of Saturday.