Gas and water vapour emissions, a low level of ash and an increase in seismic activity were recorded at the Cotopaxi volcano in Ecuador, according to officials.
Report informs citing foreign media that local seismologists are trying to calculate which regions of the country are at maximum risk.
The country's authorities have serious fears that the eruption can be compared with Vesuvius in strength.
Meanwhile, the capital's airport has already sent out warnings about the possible cancellation of flights, and the nearest settlements are preparing for evacuation.
The first volcanic eruption after 140 years of silence occurred in 2015, sending plumes of ash to the height of 5 to 8 km, according to various estimates.