This handout from Indonesia's Disaster Mitigation Agency shows Mount Agung volcano spewing smoke - AFP/BNPB
KARANGASEM – 21 November 2017: A rumbling volcano on Indonesia's holiday island of Bali spewed ash and towering clouds of smoke Tuesday, heightening fears it may erupt for the first time in more than 50 years.
Mount Agung belched smoke as high as 700 metres (2,300 feet) above its summit, as it stirred to life again after more than 140,000 people fled homes around the crater last month for fear the volcano would erupt.
Nearly 1,600 people died when Agung last erupted in 1963, but officials said Tuesday that the rumblings did not pose an immediate threat to those living in its shadow.
The alert level has not been raised, according to Made Indra, from Bali's disaster mitigation agency.
"To us this is not an eruption," Indra told AFP.
"An eruption means materials are spewing out of the mountain, and in this case there hasn't been any. This is smoke."
But local volcanologist Gede Suantika added that "people within six kilometres of the mountain (summit) should evacuate".
Agung has been rumbling intermittently since August.
Officials estimated concerns about an eruption over the past few months had cost Bali at least $110 million in lost tourism and productivity as many local residents moved to shelters.
Indonesia is home to around 130 volcanoes due to its position on the "Ring of Fire", a belt of tectonic plate boundaries circling the Pacific Ocean where frequent seismic activity occurs
In 2010 Mount Merapi -- considered one of the most active and dangerous volcanoes in the world -- erupted, killing some more than 300 people and forcing 280,000 people to flee.
Mount Sinabung on Sumatra island -- which is currently also at its highest alert level -- has been active since 2013.