Indonesia's Centre for Volcanology and Geological Hazard Mitigation recorded at least three eruptions since Friday afternoon, with the maximum height of the eruption column reaching 1200m.
An international airport in the city of Manado, less than 100km from the erupting Mount Ruang, is still temporarily closed as volcanic ash is spewed into the air.
At least three more volcanic eruptions have been recorded at the mountain since Friday. (AP PHOTO)
Satellite imagery from the Meteorology, Climatology and Geophysics Agency shows the ash has spread to the west, northwest, northeast and southeast, covering Manado and North Minahasa, according to a statement from Indonesia's Transportation Ministry.
"We are still monitoring developments in the eruption of Mount Ruang and co-ordinating with relevant stakeholders … to anticipate the necessary actions to ensure flight safety, security and comfort," said Ambar Suryoko, head of the regional airport authority.
More than 11,000 people were told to leave homes located in the affected area. A joint team from the local authorities combed the villages surrounding the volcano and evacuated residents to safer areas by boat.
Officials worry that part of the volcano could collapse into the sea and cause a tsunami, as happened in an eruption there in 1871.
Roads and buildings were covered by volcanic ash and roofs broken by debris from the eruption. (AP PHOTO)
Houses, roads and other buildings were covered by grey volcanic ash, and many roofs were broken by debris spewed from the eruption.
Mount Ruang saw at least five large eruptions on Wednesday, causing the Centre for Volcanology and Geological Hazard Mitigation to issue its highest level of alert.
People were ordered to stay at least 6km from the 725m mountain.
The observation from the agency on Friday said white smoke was rising from the main crater with medium to thick intensity.
East of the volcano, Tagulandang island could be at risk if a collapse occurred. Its residents were among those being told to evacuate.
