Volcanologists report the eruption, which sent ash up to 10km (33,000ft) into the sky, is now over. "When the lava was already here they passed by in their pickup trucks telling at us to leave, but the cars did not stop to pick up the people", said Rafael Letran, a resident of El Rodeo.
Among the fatalities were four people, including a disaster agency official, killed when lava set a house on fire in El Rodeo village, National Disaster Coordinator Sergio Cabanas said.
A vehicle is partially covered with ash after Guatemala's Fuego volcano erupted violently, in Guatemala City, Guatemala June 3, 2018. Approximately 3,300 people have been evacuated. Rescue operations had been suspended until Monday morning due to inclement weather and risky conditions.
Dozens of videos appeared on social media and Guatemalan TV showing the extent of the devastation.
One video published by news outlet Telediario, purportedly taken in the El Rodeo village, showed three bodies strewn atop the remnants of the flow as rescuers arrived to attend to an elderly man caked from head to toe in ash and mud.
"We were at a party, celebrating the birth of a baby, when one of the neighbors shouted at us to come out and see the lava that was coming", the distraught woman said. By 4 p.m. local time, lava began flowing down the mountain's side, according to The Associated Press.
In the meantime, Guatemalan President Jimmy Morales has declared three days of national mourning, according to the BBC.
A hot flow of mud, ash and gas swept down from Fuego after a new blast on Monday morning that interrupted disaster workers pulling bodies from the brown sludge that engulfed the village of El Rodeo in southern Guatemala.
The eruption of Fuego - Spanish for "fire" - on Sunday was the biggest in more than four decades, forcing the closure of Guatemala's main worldwide airport and dumping ash on thousands of acres (hectares) of coffee farms on the volcano's slopes.
The volcano is some 25 miles (40 km) southwest of the capital, Guatemala City, and is close to the colonial city of Antigua, which is popular with tourists and is known for its coffee plantations.
A pyroclastic flow is a fast-moving mixture of gas and volcanic material, such as pumice and ash.
FILE: Police officers wearing face masks guard the area after Fuego volcano erupted violently in El Rodeo, Guatemala, 3 June 2018.
Extremely hot flows of ash mixed with water and debris, blocking some roads and burning homes.
"We follow with worry the eruption of the Fuego volcano in #Guatemala", tweeted Foreign Ministry spokesman Emmanuel Nahshon, yesterday evening. Guatemala's disaster agency said 3,100 people had evacuated nearby communities, and ash fall from the eruption was affecting an area with a population of about 1.7 million of the country's 15 million or so people.