"Eruption has occurred in Bali's Mount Agung on Dec. 30 at 4:09 a.m. (local time). Exact height of ash columns hardly able to be observed," Indonesia's Meteorology, Climatology and Geophysics Agency (BMKG) said in a statement.

Heavy cloud hindered direct vision to the peak of the volcano when it erupted, it said.

The eruption was recorded by seismograph with maximum amplitude of 22 mm, lasted in three minutes and eight seconds, he added.

"Currently Mount Agung volcano is in alert status," the statement said, adding that the level III danger status has been issued on the volcano.

Indonesia's Center of Volcanology and Geological Disaster Mitigation (PVMBG) urged locals, trekkers and tourists to stay away from red zone at present, which is 4 km from the volcano crater.

The PVMBG said the red zone areas could be expanded or reduced in the following days on the basis of results monitored by its observation outpost.

The agency also warned people residing near the rivers of being cautious of potential threats as the lava and volcanic materials may flow into rivers.

Indonesia's Disaster Mitigation Agency Spokesperson Sutopo Purwo Nugroho said, volcanic ashes have affected Bali's northern regencies during rainy days.