Lumajang, East Java. Indonesian authorities on Thursday, raised the alert level for Mount Semeru in Lumajang regency, East Java, urging villagers to maintain a distance of at least 13 kilometers from the crater due to heightened volcanic activities and the potential for eruptions emitting hazardous debris.

Surveillance cameras in Pronojiwo district captured intensified volcanic activities as Java Island's tallest mountain expelled volcanic materials, triggering several eruptions throughout the day.

"We advise residents to stay vigilant for potential hot debris," said Wawan Hadi Siswoyo, an official with the Disaster Mitigation Agency (BPBD) in Lumajang regency.

The eruption's cold lava poses a risk of triggering devastating mudflows, as witnessed in previous eruptions. Villagers have been instructed to steer clear of rivers on Semeru's slope.

The alert comes after a tragic event in December 2021 when over 50 people died as Mount Semeru erupted, showering nearby areas with hot debris.