Three hikers killed in Indonesia volcanic eruption

Three hikers, including two foreigners, were killed and 10 were missing after a volcano on Indonesia's eastern Halmahera island erupted, spewing an ash cloud into the air, a local police spokesperson said.

Earlier, a rescue official said that 20 hikers, nine of them from Singapore, were reported missing after Mount Dukono on Indonesia's eastern Halmahera island erupted, spewing a smoke cloud some 10km into the air.

The area had been closed to visitors since 17 April after scientists observed an increase in volcanic activity.

The head of the government Geology Agency said the early-morning eruption was accompanied by a "booming sound" and a thick smoke column rising some 10 km from the summit of Mount Dukono in the North Maluku province.

"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.

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.

Mount Dukono is currently on the third-highest alert level 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 4km of the volcano's Malupang Warirang Crater.