Houses on the neighbouring remote island of Tagulandang were riddled with holes from falling volcanic rocks, and residents were preparing to leave at least temporarily.

“The current condition, particularly the road condition, is covered by volcanic material,” local rescuer Ikram Al Ulah said.

“Currently, many people are still wandering around. Maybe to evacuate precious goods from their house.”

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Authorities said they were rushing to evacuate 11,000 residents from the nearby area that included the remote island of Tagulandang, home to around 20,000 people.

Some residents were already trying to flee in a panic, according to officials.

“Last night people evacuated on their own but without direction due to the volcano’s eruption and materials in the form of small rocks that fell, so the people scattered to find evacuation routes,” Jandry Paendong, an official from the local search and rescue agency, said in a statement on Thursday.

He said 20 staff were helping evacuate residents along the coastline near the volcano on rubber boats.

Authorities also evacuated a prison on Tagulandang island, ferrying 17 inmates along with 11 officials and 19 residents by boat to Likupang seaport in northern Sulawesi island, according to Ikram.

The evacuation was requested by the prison chief because the facility sits directly across from the volcano, said the rescuer.

Tourists and residents were warned to remain outside a six-kilometre exclusion zone.

More than 800 people were initially taken to safety from Ruang to nearby Tagulandang island after the first eruption on Tuesday evening, before four more eruptions on Wednesday.

Paendong called for more boats and equipment, so his team could “carry out evacuation for people in the coast or near the coast” facing the volcano.

Authorities also warned of a possible tsunami as a result of the eruptions.

“The communities in Tagulandang island, particularly those living near the beach, [need] to be on alert for the potential ejection of incandescent rocks, hot clouds discharges and tsunami caused by the collapse of the volcano’s body into the sea,” Hendra Gunawan, head of Indonesia’s volcanology agency, said in a statement on Wednesday.

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Indonesian volcano lost one-third of its height

Indonesian volcano lost one-third of its height

The authorities’ fears were compounded by previous experience.

Indonesia, a vast archipelago nation, experiences frequent seismic and volcanic activity due to its position on the Pacific “Ring of Fire”, an arc where tectonic plates collide that stretches from Japan through Southeast Asia and across the Pacific basin.

The impact of Mount Ruang’s eruption led to the closure of Sam Ratulangi International Airport in Manado city, located more than 100km (62 miles) from the volcano, for 24 hours until Thursday evening.

The airport runways were shut “due to the spread of volcanic ash which could endanger flight safety,” Ambar Suryoko, head of the Manado region airport authority office, said in a statement.

The airport hosts airlines that fly to Singapore and cities in South Korea and China.

“All flights … impacted because the airport is affected by the eruption of Mount Ruang, volcanic ash,” Dimas, 29-year-old airport officer in Manado said by phone.

Budget airline AirAsia also cancelled flights to and from nine airports in eastern Malaysia and Brunei until Friday morning “due to [the] Mount Ruang eruption”, it wrote on social media platform X.