A volcano in central Indonesia spit lava and smoke high into the air early Friday, sending thousands of panicked residents racing down its fiery slopes.

One person died of a heart attack, but no other casualties were reported.

Mount Lokon in northern Sulawesi province unleashed its first powerful eruption at 10:46 p.m. Thursday, said Brian Rulrone, a disaster management agency official. That blast was followed by a second just after midnight and a third at 1:10 a.m. Friday.

Glowing lava cascaded from the mouth of the crater, triggering forest fires along its western slope, said Ferry Rusmawan, an official at the nearest monitoring post, adding that activity remained high and another eruption appeared imminent.

The 1,750-metre mountain continued to rumble during the day.

'Glowing lava flowed like flames in the darkness and it sounded like we were in a war.' —Nelson Uada, evacuee

Soldiers and police helped evacuate homes on the mountain's fertile slopes, said Jimmy Eman, the acting mayor in the nearby town of Tomohon, adding that the only victim so far was a 56-year-old woman who died of a heart attack while fleeing.

More than 6,000 people were crammed into schools, churches and other temporary shelters, and authorities said 27,000 others living within 3.5 kilometres of the crater also would be moved.

"This is the largest eruption I've ever experienced," said Nelson Uada, who was among those evacuated overnight. "It was very scary. Glowing lava flowed like flames in the darkness and it sounded like we were in a war."

Flights to the nearest international airport in Manado, the provincial capital, were not disrupted, said Lucky Podaag, an airport spokesman.

Mount Lokon has been on high alert for nearly a week and is one of Indonesia's 129 active volcanos. Its last major eruption in 1991 killed a Swiss hiker and forced thousands of people to flee their homes.

The vast archipelago nation of 240 million people sits along the Pacific Ring of Fire, a horseshoe-shaped string of seismic faults that lines the Pacific Ocean.