A volcano in central Indonesia that has been spitting ash, rocks and smoke for a week, unleashed its most powerful eruption yet on Sunday, sending panicked villagers racing back to emergency shelters.

Vulcanologists said the eruption of Mount Lokon on northern Sulawesi island shot ash and debris 3,500 meters into the air. There were no reports of anyone being hurt.

A series of blasts late Thursday and early Friday claimed the life of a woman who suffered a heart attack as she fled.

The area has been on highest alert since Monday when authorities started evacuating villages in the path of the smoke and ash. So far, around 2,500 of the 28,000 people who live on the fertile slopes have left the area.

Mount Lokon is one of the most active volcanoes in Indonesia. It erupted in 1991, killing a Swiss hiker.