On Monday, Indonesia ordered 100,000 residents living near a volcano spewing columns of ash to evacuate immediately.
"The potential for a larger eruption is imminent," the Disaster Mitigation Agency (BNPB) said.
Sutopo, a spokesman for the agency, said there had been no casualties so far and 40,000 people had left the area, but tens of thousands still needed to move.
Mount Agung last erupted in 1963, killing more than 1,000 people.
—Reuters and CNBC's Uptin Saiidi contributed to this report.
A man covers his face with a mask to shield his lungs from ash.
Mount Agung volcano erupts at Lempuyang Temple in Karangasem.
A farmer tends to his animals.
Mount Agung catapults explosions of ash to the sky.
A man places a mask over a child.
Residents at the Market in Karangasem.
Two boys observe the volcano at the Geological Agency of the Ministry of Energy and Mineral Resources.
Women gather together at an evacuation center.
Airline passengers scramble as news hits that the airport will be closed for 24 hours from Monday morning, disrupting 445 flights and some 59,000 passengers.
Bali, famous for its surf, beaches and temples, attracted nearly 5 million visitors last year, and its airport serves as a transport hub for the chain of islands in Indonesia's eastern archipelago.
Villagers walk in front of the eruption.