In pictures: Bali's Mount Agung erupts

Mount Agung in Bali's northeast erupted several times over the weekend, coating nearby resorts and villages in a thin layer of ash. Dark gray clouds spewing from the peak could be seen moving away from the capital, Denpasar, and toward the neighboring island of Lombok.

As night fell, a deep orange glow from the crater lit up part of an ash cloud that reached up to 6,000 meters (19,685 feet) into the sky. Mount Agung started showing signs of activity in September, prompting authorities to raise the volcano's emergency status to the highest level and evacuate 140,000 people living nearby. The alert was later downgraded on October 29 after a decrease in activity.

Bali's surf beaches, temples and lush forests attract about 5 million visitors each year, making the island Indonesia's top tourist destination. But Made Sugiri, from the Mahagiri Panoramic Resort, says tourist numbers have been down in recent months. "We are out of the danger zone, but like other resorts in the region, of course the eruptions cause a decrease in the number of visitors," he said.

Indonesia's disaster agency says Bali is "still safe" for tourists, noting in a statement that the emergency status for Agung remained at level 3, one below the highest, over the weekend. Despite a number of eruptions, it said volcanic activity remained relatively stable.

It was a different story for the aviation alert status, however, which was lifted on Sunday from orange to red — its highest level. Although many flights went ahead as planned, hundreds of people were stranded by cancellations. Lombok's airport had to be shut down, but officials said Bali's main airport would remain open for as long as it was still possible for planes to skirt the ash cloud.

About 25,000 people fled their homes during the latest eruptions. Authorities have warned anyone still inside a 7.5-kilometer (4.5-mile) exclusion zone around the crater to leave. Mount Agung is one of more than 120 active volcanoes in Indonesia. Its last major eruption in 1963 killed more than a thousand people.

Volcanologists described the renewed activity on Saturday as a phreatic eruption, with the expulsion of smoke caused by the heating and expansion of groundwater. On Sunday, officials said things may have progressed to a magmatic eruption, which results in the spewing of ash.

"Mount Agung ... is still spewing ash at the moment, but we need to monitor and be cautious over the possibility of a strong, explosive eruption," Indonesian government volcanologist Gede Suantika said. Soldiers and police are distributing masks to people in nearby villages and resorts to protect them from ash.