Indonesia sits on the Pacific "Ring of Fire" and is prone to earthquakes and volcanic eruptions [Reuters]

One of Indonesia's most active volcanos has erupted, forcing thousands of residents to flee their homes.

Mount Lokon, located in northern Sulawesi province, spewed lava and smoke from its crater three times late on Thursday into Friday morning, disaster agency officials said.

Lava cascaded down the volcano's slopes, setting trees ablaze, an official at the nearest monitoring post told the Associated Press news agency, adding that activity remained high and another eruption appeared imminent.

Soldiers and police helped rescuers evacuate residents living along the mountain's fertile slopes, said Jimmy Eman, the acting mayor in the nearby town of Tomohon.

One 56-year-old woman had died of a heart attack he said. But there were no other immediate reports of casualties.

More than 6,000 people who fled the eruptions were crammed into schools, churches and other temporary shelters in Tomohon. Authorities also said another 27,000 people living near the crater will be evacuated soon.

The 1,750m mountain continued to rumble later on Friday morning.

"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.''

Indonesia, a vast archipelago of 240 million people, is prone to earthquakes and volcanos because it sits along the Pacific "Ring of Fire", a horseshoe-shaped string of faults that lines the Pacific Ocean.

Mount Lokon, which has been on high alert for nearly a week, is one of the country's 129 active volcanos.

Its last major eruption in 1991 killed a Swiss hiker and forced thousands of people to flee their homes.

Source: Agencies