A column of ash soared into the daytime sky on Indonesia's Halmahera island in North Maluku province
A column of ash soared into the daytime sky on Indonesia's Halmahera island in North Maluku province AFP

A volcano in eastern Indonesia erupted on Monday, spewing a huge ash tower more than five kilometers (three miles) into the sky after authorities raised its alert level to the second-highest last week.

No damage or casualties were immediately reported but images showed a column of ash soaring into the sky on Halmahera island in North Maluku province.

Authorities said it reached more than five kilometers above the volcano's peak, one of the biggest eruptions in recent months.

The grey-black ash column was observed with "thick intensity, leaning towards the west," Geology Agency head Muhammad Wafid said in a statement Monday.

Wafid urged nearby residents to wear facemasks and glasses when going outdoors to protect against falling volcanic ash.

The volcano erupted on Saturday on a smaller scale, spewing lava, belching ash several kilometers into the night sky, and causing lightning.

The alert level remained at the second-highest of a four-tiered system on Monday after authorities raised it last week, with an exclusion zone between three and five kilometers (two to three miles) around the volcano's crater.

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

Geology Agency official Sofyan Primulyana said Ibu recorded an average of 58 eruptions per day in 2023.

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 and it remains at the highest alert level.

All of the 800 or so residents of Ruang island will be permanently relocated.