Three hikers, including two foreigners, died and 10 were missing after Mount Dukono on Indonesia’s eastern Halmahera island erupted on Friday, spewing an ash cloud about 10 kilometres into the air, a local police chief said.

“There are three dead, two foreigners and one resident of Ternate” island in eastern Indonesia, police chief Erlichson Pasaribu of North Halmahera district told Kompas TV.

Seven people had come down safely, Erlichson said, but 10 more were missing in an area declared off-limits to visitors last month after scientists observed an increase in volcanic activity.

According to Indonesia’s BNPB disaster mitigation agency, five climbers were injured in the eruption.

“The joint teams from the Regional Disaster Management Agency (BPBD) and the National Search and Rescue Agency (Basarnas) continue to conduct sweeps and evacuations of climbers in the mountain area as volcanic activity increases,” spokesman Abdul Muhari said in a statement.

Erlichson said the rescue operation was taking place in rough terrain, only accessible to vehicles part of the way up the slope.

“The rest of the way (the victims) need to be carried on a stretcher. And there is still rumbling from the eruption. It slows down our evacuation,” he said.

Lana Saria, head of the government Geology Agency, said the early-morning eruption was accompanied by a “booming sound” and a thick smoke column rising around 10 kilometres from the summit of Mount Dukono.

“The direction of the ash distribution leans northward, so residential areas and Tobelo City need to be vigilant for… volcanic ash rain,” she said in a statement.

The smoke could be dangerous for public health, Lana added, and risked disrupting transportation services.

Ring of Fire

Indonesia, a vast archipelago nation, experiences frequent seismic and volcanic activity due to its position on the Pacific “Ring of Fire” where tectonic plates collide.

The Southeast Asian country has nearly 130 active volcanoes.

Mount Dukono is currently on level two of Indonesia’s four-tiered alert system. Since December, the Centre for Volcanology and Geological Hazard Mitigation (PVMBG) has recommended that tourists and climbers do not come within four kilometres of the volcano’s Malupang Warirang Crater.

Erlichson said the hikers had ignored social media appeals and warning signs put up at the entrance to the trail to stay away.

“Local residents understand and don’t want to climb. Many (hikers) are foreign tourists who wish to create (social media) content.”