Mount Soputan volcano spewed ash 4,000 metres into the air | © Indonesia's National Disaster Agency/AFP | Handout
The state disaster agency warned people to stay at least four kilometres away but said there was no need to evacuate for the time being.
Images showed an eruption visible for miles around, with a cloud of ash climbing in a large vertical column with a mushroom-shaped top.
Soputan is around 1,000 kilometres from the town of Palu where a 7.5 magnitude earthquake triggered a tsunami that lashed the coastline killing almost 1,400 people.
Indonesia is situated on the Pacific “Ring of Fire”, a vast zone of geological instability where the collision of tectonic plates causes frequent quakes and major volcanic activity.
– AFP