Disaster agency fears death toll could climb even higher because some areas remain inaccessible by rescuers.

At least 25 people have been reported killed and 300 injured, after a volcano erupted in Guatemala, spewing ash and lava over the surrounding area, the country’s disaster management agency has said.

It was feared the death toll could climb even higher because there were communities that could not be accessed by Sunday evening, Sergio Cabanas, Conred agency’s general secretary, said.

The dead included a Conred employee and at least three children, officials said.

The army said it had evacuated 3,100 people from around the volcano, 70km south-west of Guatemala City, and posted pictures of soldiers carrying children covered in ashes from houses.

President Jimmy Morales visited Conred headquarters on Sunday evening and later following a cabinet meeting declared a state of emergency in the departments (the states) of Chimaltenango, Sacatepequez and Escuintla.

RAW VIDEO: Guatemala volcano kills at least 25 people. https://t.co/TuOu7VfnMT — The Associated Press (@AP) June 4, 2018

Al Jazeera’s David Mercer, reporting from Guatemala City, said that the volcano remains in “eruptive phase” and rescuers have scaled down the operation at nightfall on Sunday because of safety concerns.

A video posted by the Guatemalan news site Diario La Hora showed an elderly female survivor giving first-hand testimony following the eruption.

Testimonio de una de las afectadas por la erupción de hoy del volcán de Fuego. Vídeo: @DiariodeCA pic.twitter.com/YwTMB93IAV — Diario La Hora (@lahoragt) June 3, 2018

The ashfall has also forced the capital city’s La Aurora International Airport to shut down.

While the vicinity of the volcano is sparsely populated by farming villages, the ashfall is has affected an area with over a million and a half people, Mercer said.

‘Volcano of fire’

The eruption of the 3,763-metre Volcan de Fuego – meaning “volcano of fire” in Spanish – was the most powerful in recent years, according to the National Institute of Seismology, Volcanology, Meteorology and Hydrology (Insivumeh).

A September 2012 eruption of the volcano saw 10,000 people evacuated, while another in February 2015 forced the closure of the capital’s main airport.

Pictures on social media showed residents fleeing from lava and local roads, buildings and trees covered in a layer of ash, while the smoke clouds reached six kilometres above sea level.

Twenty people had to be treated in hospital for burns including at least six children, the health ministry said.

Historical records have documented the volcano’s eruptions back to 1531.

Apart from the Fuego volcano, there are two other active volcanos in Guatemala. One of them, Pacaya, is just 20 kilometers from Guatemala City.