JAKARTA: Indonesia's Ibu volcano erupted on Monday morning, spewing thick columns of grey ash several kilometres into the sky, the country's volcanology agency said.

The volcano on the remote island of Halmahera erupted at 9.12 a.m. (0012 GMT) for about five minutes, projecting ash into the sky as high as 5 km (3.1 miles), officials said.

A smaller eruption was also recorded on Friday.

The alert status of the volcano remains at the second-highest level, Hendra Gunawan, head of Indonesia's Volcanology and Geological Hazard Mitigation Centre, said in a statement.

All activities within a five-kilometre radius of the volcano were prohibited, he added.

"If it starts to rain ash, we recommend people who are near the volcano to wear a mask and glasses," Hendra said.

Footage of the eruption shared by the centre showed clouds of grey ash billowing from the crater. The official said a booming noise was also heard.

No evacuation of residents has been reported so far.

Indonesia sits on the Pacific "Ring of Fire" and has 127 active volcanoes, according to the volcanology agency.

In recent weeks North Sulawesi's Ruang volcano has erupted, spewing incandescent lava as lightning flashed from its crater. The eruption prompted authorities to evacuate more than 12,000 people living on a nearby island.

In December, more than 20 people were killed after Marapi volcano, one of Sumatra's most active volcanoes, erupted and belched grey clouds of ash as high as 3 km.