MEDAN, Indonesia (AP) -- Indonesia has raised the alert level for one of its active volcanoes to the highest after it repeatedly sent hot clouds of gas down its slopes.

A government volcanologist says Mount Sinabung in North Sumatra province unleashed volcanic ash Sunday as high as 5,000 meters and searing gas down its slope up to 2 kilometers.

Authorities have urged people to stay at least 5 kilometers away from the crater, and more than 12,300 evacuees from eight villages were packed in crowded government camps.

The 2,600-meter-high mountain has sporadically erupted since September after being dormant for three years.