There has been a minor eruption on Mount Asama in the central part of Japan. The eruption occurred shortly after 10 p.m. on Wednesday.
Meteorological Agency officials say the volcano sent smoke more than 1,800 meters up into the air.
The agency has raised the volcanic alert level to three on a scale of five.
It's calling on people within four kilometers of the crater to stay alert for possible large flying rocks, and pyroclastic flows of hot gas, ash and rocks.
Mount Asama straddles Nagano and Gunma prefectures. It's about 2,600 meters high.