A volcano on the resort island of Bali has been spewing smoke hundreds of metres into the air, threatening a major eruption.

Mount Agung, Bali's highest volcano, clouded the air with smoke 1,500m above its summit, and the volcano's alert level remains at the second highest

Thousands of people living nearby had already been forced to flee over fears it would erupt when smoke filled the air on Tuesday.

The volcano last erupted in 1963, killing 1,600 people.

People living within 7.5km (4.5 miles) of the mountain have been told to evacuate, senior volcanologist Gede Suantika said.


Image: Farmers living near the base of the volcano have had to flee

Mass evacuations also took place in September when Mount Agung showed signs of erupting, forcing more than 120,000 from their homes.

Many had since returned after the volcano appeared to be calming, but fresh fears of eruption have caused more chaos for residents.

Around 25,000 people have been evacuated to more than 200 temporary shelters.

"We will continue to see eruptions like this on similar scales, but we cannot predict when Mount Agung will really erupt," Suantika told AFP.

Image: Increasingly frequent tremors stoke fears an eruption may be imminent

Bali's airport is operating normally, but some airlines have cancelled their flights.

Indonesia sits on the so-called Pacific Ring of Fire and has 127 active volcanoes - more than any other country.

Mount Sinabung on Sumatra island has been active since 2013 and is currently at its highest alert level.