About three three dozen flights between Australia and Bali have been cancelled or delayed following a massive eruption of one of Indonesia's most active volcanoes.
Mount Lewotobi Laki-Laki spewed hot ash and smoke reaching 10,000 metres high when it erupted on Tuesday evening, affecting airspace between the two countries.
About a dozen Jetstar flights between capital cities and Bali scheduled for Wednesday morning were cancelled, while flight trackers showed delays of up to three hours for about another dozen flights scheduled this afternoon and evening.
"At this stage, forecasts show the ash cloud is expected to clear by later tonight," the airline said in a written statement on its website.
The airline said it reached out to impacted customers to discuss their options.
Virgin Australia also cancelled all flights between Bali and Sydney, Melbourne, and Brisbane, while Qantas-operated flights showed delays.
Singapore Airlines, Air India, and Air New Zealand were among the international airlines that also cancelled flights to and from Bali because of the ash cloud.
Air New Zealand said it was working to re-book impacted customers.
"The safety of our customers and crew is our top priority and we are closely monitoring the situation," said Air New Zealand's chief operating officer Alex Marren in a statement.
The Indonesian government also closed the Fransiskus Xaverius Seda airport on Flores island to ensure the safety of its passengers.
No casualties reported
Local authorities raised volcanic activity alerts to their highest level before Mount Lewotobi Laki-Laki, in the country's south-central region, began to emit a massive plume of smoke that could be seen from 150 kilometres away.
Authorities expanded the danger zone surrounding the volcano — marking where volcanic activity made the area unsafe — to 8 kilometres from the crater.
The local disaster-mitigation agency evacuated two villages near the volcano and said no casualties were reported.
"Streets in the two villages were filled with thick ash, gravel, and sand," Avi Hallan, an official at the agency, said.
Residents were warned to be vigilant about heavy rainfall triggering lava flows in rivers originating at the volcano.
Videos of the eruption that began around 5:30pm local time showed villagers watching as the ashes expanded into a mushroom-shaped ash cloud.
Local villager Frans Kino said it was the first time he had seen an eruption this big on the mountain.
"It looks like this eruption is quite large. Up there, it must be dark," he said, pointing to where he lived up the hill.
Surge in seismic activity
Indonesia's Geology Agency said in a written statement that the volcano unleashed 10,000 metres of thick grey clouds on Tuesday afternoon, following significant volcanic activity.
It reported 50 deep volcanic earthquakes in 2 hours, compared to the daily average of eight to 10 events.
A previous eruption of Mount Lewotobi Laki Laki in November killed nine people and injured dozens.
Lewotobi Laki-Laki — whose name means "male Lewotobi" — is a twin volcano to Lewotobi Perempuan, which translates to "female Lewotobi".
The 1,584-metre mountain is on the Flores island of Indonesia's East Nusa Tenggara province and is just one of the 120 active volcanoes along seismic fault lines in the Pacific Basin known as the "ring of fire".
Indonesia is an archipelago of 270 million people with frequent seismic activity.
ABC/AP