Mount Sinabung in Indonesia has been erupting since Monday, sending a column of black ash and smoke 3,500 meters (11,482 feet) above the summit into the sky over Sumatra Island, with activity continuing on Tuesday.
There were no immediate reports of casualties, evacuations, or flight disruptions. But residents and visitors were advised against activity within 6 kilometers (3.7 miles) of the summit in Karo District, North Sumatra.
Roads, vehicles, and buildings in several Karo villages affected by the eruption were coated in grey ash. Local authorities handed out masks to residents.
Officials raised the volcano alert to “Watch,” the second-highest level for volcanic activity, widening the exclusion zone around the 2,600-metre (8,530-foot) mountain.
“This eruption is considered an initial eruption, and it is possible that a larger eruption could occur,” Lana Saria, chief of Indonesia’s Geological Agency, said in a statement on Monday.
The agency had recorded visual signs of increased activity at Mount Sinabung in mid-August, including dozens of earthquakes, and had already extended the recommended radius for public activity.
About 30,000 people have been forced from their homes around Sinabung in recent years because of volcanic activity.