Mount Ibu erupted on Saturday evening, sending ash 4km high, as streaks of purple lightning flashed around its crater, according to information and images shared by Indonesia’s volcanology agency.

A joint team comprised of police, military, and search and rescue officials were dispatched to the area to evacuate residents from surrounding villages, Abdul Muhari, from the disaster mitigation agency, said in a statement.

Photos shared by the disaster agency showed authorities assisting the elderly, while other residents were moved in pick-up trucks and accommodated in emergency tents for the night.

The agency did not provide any information about how many people had been moved, but authorities have recommended that a 7km radius be cleared.

Indonesia’s volcanology agency raised the alert level of the volcano to the highest level on Thursday, after Ibu erupted multiple times earlier this month.

Ibu’s activities follow a series of eruptions of different volcanoes in Indonesia, which sits on the Pacific “Ring of Fire” and has 127 active volcanoes.

Flash floods and cold lava flow from Mount Merapi, one of the most active in West Sumatra province, covered several nearby districts following torrential rain on May 11, killing more than 60 people.

In recent weeks, North Sulawesi’s Ruang volcano has also erupted, spewing incandescent lava. The eruption prompted authorities to evacuate more than 12,000 people on a nearby island.