Guatemala’s disaster agency has said superhot volcanic material is once again flowing down the south side of the Volcano of Fire.

The report came shortly after the agency announced new evacuations on Tuesday afternoon and pulled back rescuers, police, journalists and others from towns destroyed after Sunday’s volcanic eruption.

A short video showed a steady flow of traffic away from the volcano to the sound of a blaring alarm.

The agency said at least 70 people were killed by similar flows of searingly hot gases and ash on Sunday.

Guatemala’s seismology and vulcanology institute said the new flow of searing hot volcanic material down the south-eastern slopes is expected to produce a “curtain” of ash that the wind will carry to the west and north-west.

The institute’s latest bulletin says the blowing ash could reach heights of about 20,000ft above sea level. It warns civil aviation authorities to closely monitor and take precautions regarding air traffic.