President Jimmy Morales said he had convened his ministers and was considering declaring a state of emergency in the departments of Chimaltenango, Escuintla and Sacatepequez.
Steaming lava flowed down the streets of the village of El Rodeo as emergency crews entered homes in search of trapped residents, a video on a different local media outlet showed.
"Currently the volcano continues to erupt and there exists a high potential for (pyroclastic) avalanches of debris," the disaster agency said via Twitter, quoting Sanchez, the director of the seismology and volcanology institute.
The eruption forced the Guatemala City's La Aurora international airport to shut down its only runway due to the presence of volcanic ash and to guarantee passenger and aircraft safety, Guatemala's civil aviation authority said in a Tweet.
The volcano is located 25 miles southwest of the capital Guatemala City and is close to the colonial city of Antigua, popular with tourists and known for its coffee plantations.