The volcano, located on an island in the eastern North Maluku province, has been erupting almost every day since early May. Authorities have raised the alert to the highest level as the number of eruptions and deep volcanic earthquakes have significantly increased.

Thursday's eruptions sent ash clouds up to 1,200 metres (4,000 feet) into the air, said Muhammad Wafid, chief of Indonesia's Geology Agency. Photos and videos recorded by the agency from an observation post showed bursts of incandescent red lava with some lightning during the eruptions.

Authorities have urged people to stay at least 7 kilometers (4.5 miles) from the 1,325-metre (4,347-foot) -high volcano.

More than 1,900 people have been evacuated from three villages close to the volcano, according to the National Disaster Management Agency. Thousands of hectares (acres) of farmland have been affected by the eruptions.

Indonesia, an archipelago of 270 million people, has 120 active volcanoes. It is prone to volcanic activity because it sits along the “Ring of Fire”, a horseshoe-shaped series of seismic fault lines around the Pacific Ocean.