Bali's Mt Agung volcano's eruptions have sent a plume of volcanic ash and steam more than 6000 metres into the skies above the popular holiday island, sparking flight disruptions.
Ash covered roads, cars and buildings near the volcano in the northeast of the island on Sunday, while scores of flights were cancelled and overnight a red glow of what appeared to be magma could be seen in photographs by Antara, the state news agency.
"The activity of Mount Agung has entered the magmatic eruption phase. It is still spewing ash at the moment but we need to monitor and be cautious over the possibility of a strong, explosive eruption," said Gede Suantika, an official at the volcanology and geological disaster mitigation agency.
Agung rises majestically over eastern Bali at a height of just over 3000 metres. When it last erupted in 1963 it killed more than 1000 people and razed several villages.
Australia's Bureau of Meteorology's Volcanic Ash Advisory Centre (VACC) in Darwin issued maps showing an ash cloud heading southeast over the neighbouring island of Lombok, away from Bali's capital, Denpasar, where the main international airport is located.
Indonesia also upgraded its Volcano Observatory Notice for Aviation (VONA) to red, its highest warning, and said the ash-cloud top could reach 6142 metres or higher.
However, officials said the airport would remain open for now as the ash could be avoided. All domestic flights and the airport itself were operating as "normal" and tests for ash had been negative, it said.
After resuming flights on Sunday morning, Virgin Australia again cancelled flights on Sunday afternoon following a change in the aviation colour code from orange to red.
AirAsia also cancelled its remaining flights to Bali and Lombok.
Qantas and Jetstar flights were continuing as of Sunday afternoon but Jetstar warned on its website that flights could be subject to change at short notice for safety reasons.
Indonesia's flag carrier Garuda said it was cancelling all flights to and from Lombok, which was closed.