The Lokon volcano erupts near Tomohon on July 15, 2011.
An Indonesian volcano erupted late on Thursday, spewing rocks, lava and ash hundreds of metres into the air, an official said, three days after its alert status was raised to the highest level.

There has been a significant rise in volcanic activity at Mount Lokon on Sulawesi island since June 9, prompting hundreds of people to evacuate the area.

'There was a big eruption around 10.31pm local time (1531 GMT, 11.31pm Singapore time), which saw ash, sand and rocks thrown 1,500m into the air,' government volcanologist Kristianto told AFP.

Grass and shrubs in an area stretching 500m around the volcano were on fire but there was no immediate danger to people living nearby, he said. The volcano's status was raised to its highest red alert level after it spewed ash 500m into the air over the weekend, leading to a 3.5km evacuation zone being established in case of a bigger eruption.

'There is no mass panic because the community has already been warned of the situation and we are continuing to evacuate people,' added Dr Kristianto, who like many Indonesians uses only one name.

Around 28,000 people live within the evacuation zone. The 1,580m Mount Lokon is one of the most active volcanoes in Indonesia. It erupted in 1991, killing a Swiss tourist