Parents from the Enrique Rebsamaen primary and secondary school in Mexico City waited in fear as rescuers searched the rubble from the three-story structure that collapsed Tuesday in a 7.1 magnitude earthquake.
As of early Wednesday, the bodies of 21 children and four adults had been pulled from the debris. Many others remained missing.
Noises could be heard from beneath the concrete, glass and twisted metal, although rescuers were unsure if it was children crying for help or the structure shifting.
Soldiers attempted to secure the remaining wing of the school by wedging wooden beams into the structure.
A group of extraordinary individuals moved in once the beams were set. Among them was 29-year-old Pedro Serrano, a doctor who made his way through the debris to look for any survivors.
"We dug holes, then crawled in on our bellies," he said.
"We managed to get into a collapsed classroom. We saw some chairs and wooden tables," Serrano added. "The next thing we saw was a leg, and then we started to move rubble and we found a girl and two adults — a woman and a man."
The rescuers left the bodies behind as none of them were alive and freeing them was impossible.
Volunteers worked through the night to check for any survivors, occasionally asking for silence so they could listen for signs of life.
Tuesday’s earthquake marked Mexico’s deadliest earthquake in decades as the number of confirmed deaths climbed to 217.
The Associated Press contributed to this report.