In the debris and dust of collapsed buildings, the search continues for survivors of Tuesday's 7.1 magnitude earthquake in central Mexico.

"They're using their hands to dig into the rubble," said Victor Martinez, who works in Mexico City for the relief group World Vision.

He described seeing first responders and volunteers desperately searching the crushed classrooms of the Enrique Rebsamen school, in the south of the capital.

Related: Mexico quake kills at least 225; one girl found alive in school rubble

At least 25 bodies have been recovered: most of them children.

"There are hopes that children are still alive... and teachers."

World Vision, whose U.S. headquarters is based in Federal Way, is organizing volunteers to search for survivors, set up shelters, and distribute food and hygiene kits.

Martinez says the charity has operated in Mexico for 35 years and plans long-term help too, including providing psychologists to help children cope with the disaster. For now, even the youngest survivors are assisting in the recovery.

"You can see people of all ages, distributing food, water, and tools, supplies as well," said Martinez. "That will help the rescuers continue their efforts."