SIDOARJO, Indonesia (AP) — Indonesian rescue authorities made the tough decision on Thursday to start using heavy machinery to move large sections of a collapsed school, with no more signs of life from beneath the rubble and nearly 60 teenage students still unaccounted for three days after the building caved in.

The decision had been made in consultation with the families of those still missing, Indonesian Coordinating Minister for Human Development and Cultural Affairs Pratikno told reporters at the scene in Sidoarjo.

For Mohammad Solehoddin, whose son Ahmad Suafi still hasn't been found, ramping up the effort with heavy excavators seemed the best chance of still possibly finding the 17-year-old alive.

“By removing the large parts of concrete, we hope our sons will be found,” said the 47-year-old, who waited with his wife and other anxious parents in an area of the school that was undamaged, with the sounds of the machinery at work audible in the background.

Five students were rescued Wednesday by workers who tunneled into the rubble using only hand tools. Pratikno said on Thursday that work would proceed with extreme caution even though no more signs of life could be detected.

“In any case, we will be very, very careful when using the heavy machines,” said Pratikno, who only goes by one name as is common in Indonesia.

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

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

Five people have been confirmed killed so far, and of about 105 who were injured, more than two dozen are still hospitalized, with many said to have suffered head injuries and broken bones.

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.

Most rescues typically happen within 24 hours after such disasters, with chances of survival decreasing steadily as time progresses.

Solehoddin said that he had had been at the scene since late Monday, having rushed there from his village on a nearby island after hearing the news. On Tuesday, when he was close to the collapsed section as the parent representative chosen to observe, he said he had been able to hear voices from those trapped.

He last saw his son two weeks ago when the teenager made a surprise visit home, because he said he missed his mother’s cooking. Now, he said, he’s left with prayers that he will see him again.

“I leave it to God,” he said. “What else can we do?”

Nearly 220 workers were on the scene Thursday with ambulances on hand ready to take any survivors found quickly to the hospital. But authorities also brought in large quantities of body bags, a tacit acknowledgement that the odds of finding anyone left alive were rapidly diminishing.

"We are no longer considering the possibility of survivors remaining, but we will still proceed with caution, said Suharyanto, the head of Indonesia’s National Disaster Mitigation Agency, who also goes by one name.

The numbers of missing have fluctuated widely over the course of the three-day recovery effort, and Suharyanto conceded that authorities still aren't certain how many students may be buried, having made their estimate based on school attendance figures and information from families.

“We really hope that these 59 people are not there under the rubble,” he said. "It happened previously that parents reported their children missing but turned out that their children were somewhere else — I do hope and pray that they are not there.”

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Alangkara reported from Jakarta. Associated Press journalists Fadlan Syam and Achmad Ibrahim in Sidoarjo, Indonesia, and David Rising in Bangkok, contributed to this report.