As the Volcan de Fuego continued to belch and rumble, hundreds of rescuers in hard hats and with shovels fanned out to search for the missing, combing through ash and rock that cascaded down the volcano's steep slopes on Sunday and buried villages and vehicles.
"We don't rule out the possibility of some person alive, but the condition in which the homes are [in] makes that possibility pretty unlikely," Julio Sanchez, a spokesman for the fire department in Escuintla, told reporters.
Officials said 192 people were still unaccounted for.
The U.S. military was expected to fly children burned by hot ash and volcanic debris to the Galveston Shriners Hospital pediatric burn center in Galveston, Texas.
The volcano, about 25 miles from Guatemala City, the country's capital, is one of the most active in the region. But locals said they have never witnessed an eruption as powerful as the one that occurred around 2 p.m. on Sunday.
When the Kilauea Volcano on the Big Island of Hawaii erupted May 6 and sent a river of hot lava flowing over roads and houses as it cut a wide swath to the Pacific Ocean, many people had already heeded evacuation orders and escaped danger.
But authorities in Guatemala said that while they had been monitoring the volcano since early Sunday morning, they never expected it would explode with such violence. No evacuation orders were issued until it was too late for many, officials said.
The eruption sent a plume of smoke and fire soaring more than 3,000 feet in the sky and sent 1,300-degree ash and volcanic particles cascading down the slopes of the 12,346-foot volcano.
Homes and structures in villages at the foot of the volcano, including hard-hit El Rodeo, were covered in ash and mud, leaving the once lush, green vegetation coated in gray.
Officials are also worried that rain in the forecast could trigger mudslides like one in the San Pedro Soloma area that killed 12 people a year ago, and another that struck in the mountain Village of El Cambray in October 2015 that killed 280 people and destroyed more than 200 homes.