Mount Lewotobi Laki-laki, on Flores Island in East Nusa Tenggara province, erupted at midnight on Sunday (3am Monday AEDT), belching a fiery-red column of lava, volcanic ash and incandescent rocks, Hadi Wijaya, a spokesperson for The Center of Volcanology and Geological Hazard Mitigation (PVMBG), said.
"After the eruption, there was power outage and then it was raining and big lightning which caused panic among residents," he told Reuters, adding that the authority had raised the status of the volcano to level IV or the highest.
The agency has recommended a seven-kilometre radius be cleared.
Thick volcanic ash covered roads and buildings in one of the villages near the volcano. (AP PHOTO)
Fiery lava and rocks hit the nearest settlements around four kilometres from the crater, burning and damaging residents' houses, Hadi said.
As of Monday afternoon AEDT at least 10 people had died, said local official Heronimus Lamawuran, adding the eruption had affected seven villages.
"We have started evacuating residents since this morning to other villages located around 20km from the crater," he said.
Images shared by authorities showed the evening sky over the volcano turned red due to the eruption, while footage showed some wooden houses on fire and mask-wearing residents being evacuated. Thick volcanic ash covered roads and buildings in one of the villages, more footage showed.
Indonesia's disaster agency warned of potential flash floods and cold lava flows in the coming days, agency spokesperson Abdul Muhari said.
The local government has declared a state of emergency for the next 58 days, Abdul said, meaning the central government could help provide aid to the 10,000 affected residents. Authorities are still gathering data on the number of evacuees.
The nearest airport, located in the town of Maumere, had been temporarily closed, he added.
Indonesia sits on the "Pacific Ring of Fire", an area of high seismic activity atop multiple tectonic plates. This eruption follows a series of eruptions.
In May, a volcano on the remote island of Halmahera, Mount Ibu, caused evacuation of people from seven villages.
North Sulawesi's Ruang volcano has also erupted in May and prompted authorities to evacuate more than 12,000 people.
Flash floods and cold lava flow from Mount Marapi in West Sumatra province, covered several nearby districts following torrential rain on May 11, killing more than 60 people.
