Rescuers were racing against time on Thursday to extricate some 60 teenagers trapped under the remains of an Islamic boarding school that collapsed earlier this week due to foundation failure, disaster authorities said.

The Al Khoziny school, located in the East Java town of Sidoarjo, some 480 miles east from the capital Jakarta, collapsed when its foundations could not support ongoing construction work on the upper floors, cratering upon dozens of students who were praying and trapping them under rubble.

Abdul Muhari, spokesperson with the disaster mitigation agency, said in a statement on Thursday that 59 people remained trapped, based on the school’s list of absences and missing person reports filed by families.

Rescuers found no signs of life on Thursday after calling out the names of the victims and using motion detectors and scanners to track movements or vital signs, search and rescue agency official Emi Freezer told Reuters.

In signature orange uniforms, rescuers crawled through narrow tunnels to find students trapped under rubble, according to photos distributed by the agency.

Late on Wednesday, Yudhi Bramantyo, operations director at the agency, said the total death toll from the collapse had reached six, although the country’s disaster mitigation agency said on Thursday it was still at five.

“We can’t let our minds wander. Maybe there is still hope for our little brothers,” Bramantyo said.

A crane has been deployed on Thursday to lift light, unconnected debris, Freezer said. Al Khoziny is an Islamic school known locally as a pesantren.

Indonesia, the world’s largest Muslim-majority nation, has a total of about 42,000 pesantren, serving 7 million students, according to data from the country’s religious affairs ministry.

Waiting along with other anxious parents convening around a whiteboard showing a list of survivors, Ahmad Ikhsan, 52, was still holding out hope that his 14-year-old son, Arif Affandi, would be found.

“Until now, I haven’t heard about my son,” he said. “I believe my son is still alive.”