The country's Center for Volcanology and Geological Hazard Mitigation shared an image of the thick column of grey ash towering among white clouds around Mount Ibu, located on the island of Halmahera in North Maluku province.

No damage or casualties were immediately reported from the two eruptions, which took place within the span of an hour. The first occurred at 10:45 am (0145 GMT).

"The eruption is still ongoing at the time of this report," the volcanology centre said in a statement.

Locals were urged not to go within five kilometres of Ibu's crater, the statement added.

Mount Ibu is currently at the second-highest level of alert after the authorities lowered it last week.

Ibu is one of Indonesia's most active volcanoes, erupting more than 21,000 times last year.

More than 700,000 people lived on Halmahera island as of 2022, according to official figures.

Indonesia, a vast archipelago nation, experiences frequent seismic and volcanic activity due to its position on the Pacific "Ring of Fire".

Last month, Mount Ruang in North Sulawesi province erupted more than half a dozen times, forcing thousands of residents of nearby islands to evacuate.