The disaster agency said 3,265 people had been evacuated.
An estimated 25 people, including at least three children, have been killed and almost 300 injured in the most violent eruption of Guatemala's Fuego volcano in more than four decades.
At least 25 people were killed, 20 others injured and some 1.7 million residents have been affected by the eruption of Guatemala's Fuego volcano, the most violent in recent years, according to government authorities.
The Guatemalan military said it was providing assistance from rescue operations to setting up temporary shelters and clearing volcanic ash from La Aurora airport's runway.
Earlier, Reuters reported that the aviation authorities closed Guatemala City's worldwide airport because of the danger posed to planes.
President Jimmy Morales is considering declaring a state of emergency.
Residents of El Rodeo, about eight miles (12 kilometers) downslope from the crater, said they were caught unaware by the fast-moving hot ash and rock when the volcano west of Guatemala City exploded Sunday, sending towering clouds into the air.
Guatemala's Volcan de Fuego - Volcano of Fire - erupted spectacularly Sunday, shooting a plume of ash and gas almost six miles into the sky and spreading ash and debris across towns and farms more than 10 miles away from the volcano. Hundreds of rescue workers, including firefighters, police and soldiers worked to recover bodies from the still-smoking lava.
The eruption sent ash billowing over the surrounding area, turning plants and trees gray and blanketing streets, cars and people.
This is Guatemala's deadliest such event since 1902, when an eruption of the Santa Maria volcano killed thousands of people.
Fuego is one of Latin America's most active volcanoes.
The Fuego volcano of Guatemala erupted on Sunday afternoon, leaving at least 31 dead, buried neighborhoods, and ash columns over 6,000 meters high. "I think they ended up buried", Consuelo Hernandez, a resident of the village of El Rodeo, told the newspaper Diario de Centroamerica.
The alert level was raised to red in nearby cities and towns of Escuintla, Alotenango, Sacatepéquez, Yepocapa and Chimaltenango on Tuesday.
Disaster agency spokesman David de Leon said 18 bodies had been found in San Miguel Los Lotes.
No shaking has been felt in the capital of Guatemala, located in the north-west of the central American country.