Mount Lokon volcano on Indonesia's Sulawesi island erupted early Friday, February 10 with a loud explosion and spewing ash 2 kilometres up in the sky, state news agency Antara reported.

The 1,578-metre volcano erupted at 8:20 am local time (0020 GMT), but no casualties were reported.

"Volcanic activity had been increasing since yesterday before it erupted this morning" Warno, a volcano observation staff, was quoted as saying. "The height of the ash-smoke plume is estimated to be about 2,000 metres," said Warno, who like many Indonesians goes by only one name.

Residents to the east of the crater within a 3.5-kilometre radius have been advised to vacate their homes, the Centre of Vulcanology and Geological Disaster Mitigation said on its website.

The Indonesian archipelago is spreading along the seismically active Ring of Fire in the western Pacific, and has the world’s highest density of volcanoes. Of its 500 volcanoes, 128 are active and 65 are listed as dangerous.

Mount Lokon erupted several times last year, most recently in December, but there were no casualties, according to The Nation.