Mount Sinabung, a volcano in western Indonesia, has been spewing clouds of searing gas high into the air in recent days, prompting the evacuation of thousands from the danger zone.
Indonesian authorities said on Wednesday that the volcano has let out powerful new bursts, counting more than 50 separate eruptions. No injuries reported but the officials have urged villagers to stay out of the 7km danger area.
Nearly 3,000 people have been evacuated from their homes after the officials placed the volcano at the highest alert level last week, and has been closely monitoring its activity.
Hot ash tumbled down Sinabung's slopes up to 2.5 kilometres from its smouldering mouth, government volcanologist Surono told the Associated Press news agency.
The growing size of the lava dome is very unstable," said Surono, adding that smouldering rocks mixed with hot gases may tumble down at any time.
Mount Sinabung sits on Sumatra, one of Indonesia's main islands, and is among about 130 active volcanoes in the country.
Sinabung erupted in 2010 after 400 years of silence and has erupted several more times since 2013. When it erupted in 2014, 16 people died. Thousands of people fled their homes during this activity and some still live in shelters.
"Volcanic activity is still high, triggering tremors," district military commander Lieutenant-Colonel Asep Sukarna told AFP.
Indonesia sits in the Pacific’s "Ring of Fire," where tectonic plates collide and cause frequent seismic and volcanic activity.