Indonesia's Mount Lokon erupted to spew hot lava and volcanic ash as high as 1,500 metres (5,000 feet) in the north of Sulawesi island, prompting panicked residents to flee the agricultural area, a government official said on Friday.

"The eruption has set ablaze the forests around the crater," said Sutopo Purwo Nugroho, spokesman for the National Disaster Mitigation Agency.

There are no immediate reports of casualties, he added.

The first major eruption of the 1,579-metre-high volcano, just before midnight on Thursday, woke up residents who put on warm sweaters and hats before fleeing their houses.

The government is planning to distribute masks and tents for people who have taken refuge in school buildings, Nugroho said.

The international airport in the provincial capital of Manado, a tourist destination for nearby coral reefs of Bunaken, was still operating normally, an airport official told Reuters.

The centre of vulcanology and disaster mitigation has raised the status of the volcano to its highest alert level, advising evacuation for about 28,000 people living within 3.5 kilometres of the Tompaluan crater.

Indonesia, the world's fourth most populous country, is on the Pacific "Ring of Fire" and is frequently prone to natural disasters such as earthquakes, volcanoes, tsunami and floods.

Reuters