Mount Merapi volcano has erupted for a third time, with local people reportedly saying this was louder and stronger than the previous eruption on Tuesday.
The latest eruption happened at around 0100 on Saturday (1800GMT Friday).
Agence France Presse reported that it caused panic, with hundreds of people, including police and soldiers, trying to flee in cars or on motorbikes.
Ash was raining down in Yogyakarta, about 30km (19 miles) away.
But authorities say Yogyakarta is safe. The head of the monitoring body has said the risk remains limited to the 10km zone around the mountain.
Nearer that zone, though, people felt more in danger.
There had been a number of small eruptions earlier on Friday but with no casualties reported.
Earlier, officials said two people who suffered burns from Tuesday's eruption had died from their injuries, bringing the confirmed death toll to 35.
(BBC/VOVNews)
