Chile has issued a red alert for a volcano on the border with Argentina that has become increasingly active.
The Copahue volcano, which sits in the Andes cordillera, straddling the border with Argentina's Neuquen province, started spewing ash and gas on Saturday.
Officials issued a yellow and orange alert at first but Chile's emergency office ONEMI raised the alert on Sunday in the Biobio region after it registered seismic activity on Saturday night and a cloud of ash billowed almost a mile high.
"Authorities have overflown the volcano area and the alert is still red," Gilda Grandon of the ONEMI's BioBio unit told The Associated Press. "We have noted some drop in the ash plume but the alert level is maintained because a full eruption is not ruled out."
The Mining Ministry's Sernageomin geology unit has recommended careful observation of a 9-mile radius around the active crater in case of mudflows of volcanic fragments. Officials say there's no need yet to evacuate.
The 9,833-feet high Copahue erupted in 1991. The volcano became highly active with blasts and gases in 2001 in its worst activity in more than 20 years.
A volcano in the Caulle Cordon of southern Chile erupted violently last year, forcing the cancellation of hundreds of flights and the evacuation of more than 3,500 people.