Indonesia’s Mount Semeru volcano has erupted, spewing ash into the sky and forcing evacuations on the country’s main island, Java.
The volcano’s warning level was raised to the highest level, indicating that its activity had increased.
Although no injuries have been reported, nearly 2,000 people have been evacuated from the area surrounding the volcano.
As “hot avalanches” of lava poured from Semeru, people were advised to stay at least 8 kilometres (5 miles) away.
The threat level has been raised from three to four, which means the danger now threatens people’s homes, according to a spokesman for Indonesia’s Center for Volcanology and Geological Hazard Mitigation (PVMBG).
According to the organisation, a bridge that was being rebuilt following a previous eruption had been severely damaged.
Volcanic ash mixed with monsoon rain was falling on nearby villages and 1,969 people, including children and seniors, had been evacuated, the National Disaster Mitigation Agency (BNPB) said.
At least six villages had been affected, it added.
Videos of the event showed the sky turning black as a massive plume of ash blocked the sunlight.
Japan issued a tsunami warning for its southernmost islands after the eruption, but meteorologists said no tidal changes had been observed.
Mount Semeru, in East Java province, began erupting at about 02:46 local time (19:46 GMT), authorities said.
Indonesia sits on the Pacific “Ring of Fire” where tectonic plates collide, causing frequent volcanic activity as well as earthquakes.
Semeru – also known as “The Great Mountain” – is the highest volcano in Java at 3,676m (12,060ft) and one of the most active. Its last erupted exactly one year ago, killing at least 50 people and leaving streets filled with mud and ash.
The eruption also follows a series of earthquakes on the west of Java island, located about 640 km (400 miles) east of Indonesia’s capital Jakarta, including one last month that killed more than 300 people.