Panicked residents continued to flee the area around Mount Lokon in the north of Sulawesi island on Friday, after the volcano erupted just before midnight on Thursday local time, spewing hot lava and ash as high as 1,500 meters.
"The eruption has set ablaze the forests around the crater," said Sutopo Purwo Nugroho from the National Disaster Mitigation Agency. He said there had been no immediate reports of casualties.
Many have taken refuge in school buildings where the government plans to distribute masks and tents. Evacuation has been advised to some 28,000 people who live within 3.5 kilometers of the crater.
Over 4,000 people have already been evacuated. Mount Lokon last erupted in 1991, killing a Swiss tourist. It is one of Indonesia's most active volcanoes.