Volcano on Indonesia's Sumatra unleashes burst of hot ash down slopes; no injuries reported

FILE - In this Friday, June 5, 2015, file photo, an Indonesian man takes pictures of Mount Sinabung as it releases volcanic materials in Tiga Serangkai, North Sumatra, Indonesia. Indonesia has raised the alert status of the volcano in the western part of the country to the highest level following a sharp increase in activity this week. (AP Photo/Binsar Bakkara, File) (The Associated Press)

Mount Sinabung spews volcanic materials from its crater in Tanah Karo, North Sumatra, Indonesia, Wednesday, June 10, 2015. Authorities say they are closely monitoring the volcano after it was placed at the highest alert level last week. (AP Photo/Andi Jatmiko) (The Associated Press)

TANAH KARO, Indonesia – A volcano in western Indonesia that has been spewing clouds of searing gas high into the air has let out a new powerful burst.

Authorities say they are closely monitoring Mount Sinabung on Sumatra, one of Indonesia's main islands. It was placed at the highest alert level last week.

Government volcanologist Surono said hot ash tumbled down Sinabung's slopes up to 2.5 kilometers (1.5 miles) from its smoldering mouth on Wednesday. He is urging villagers to stay out of the main danger zone, which stretches 7 kilometers (4 miles) to the southeast of the crater. No injuries have been reported.

The volcano has been shooting smoke and ash more than 500 meters (1,640 feet) into the air since Monday.

Sinabung is among some 130 active volcanoes in Indonesia.