Indonesia's Mount Merapi, one of the world's most active volcanoes, erupted Thursday as fiery red molten lava streamed down from the crater and it belched clouds of grey ash 2,000 metres (6,500 feet) into the sky.
Authorities did not raise the rumbling volcano's alert status after the early-morning eruption, but they advised commercial planes to take caution in the area.
But any activity at Merapi raises concern and local residents were ordered to stay outside a three-kilometre no-go zone around the rumbling crater near Indonesia's cultural capital Yogyakarta.
Volcanic ash rained down on a 10-square kilometre area, according to the Volcanology and Geological Hazard Mitigation Centre.
Mount Merapi's last major eruption in 2010 killed more than 300 people and forced the evacuation of some 280,000 residents.
It was Merapi's most powerful eruption since 1930, which killed around 1,300 people, while another explosion in 1994 took about 60 lives.
The Southeast Asian archipelago has more than 17,000 islands and islets -- and nearly 130 active volcanoes.
It sits 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.