Around 100,000 people have been evacuated and Indonesian authorities have reportedly raised the state of alert to its highest level, expanding the exclusion zone around the volcano.
Dark smoke and ash is billowing up to 3,400 above the mountain’s summit according to authorities.
The National Board for Disaster Management raised the alert to level four from 06:00 local time due to "the possibility and imminent risk of disaster", the BBC said.
“The rays of fire are increasingly observed at night. This indicates the potential for a larger eruption is imminent”, it said on its Facebook page.
The UK Foreign Office warned that ash clouds had caused disruption to flights and urged Brits to contact their airline or travel agent before flying.
In a statement it added: “Mount Agung in East Bali has been erupting since November 21 and local authorities raised the alert level to level 4 (the highest level) on 27 November 2017.
“Ash clouds have caused airport closure for periods in both Bali and Lombok and disruption to flights in the region. The authorities are monitoring the situation closely and airports in the region are likely to continue to be closed for periods of time. You should confirm your travel arrangements directly with your airline or travel agent before travelling to the airport.
“You should monitor local media reports, follow the advice of the local authorities and stay outside the existing exclusion zone, which extends between 8 and 10 kms from the crater. Volcanic activity may escalate. Volcanic ash clouds could continue to cause flight disruption and may result in further airport closures in the region.”
Some 445 flights have been cancelled according to airport authorities, affecting 59,000 travellers. Indonesia’s national hotel association said stranded tourists staying at member hotels could stay one night for free.
