The Japan Meteorological Agency said Mount Asama in central Japan erupted late on Wednesday and issued a warning not to approach the volcano.
The agency issued a level 3 warning on a scale of up to 5 following the eruption that occurred around 10:08 p.m. (1308 GMT).
There were no immediate reports of damage in the sparsely populated vicinity.
(The story has been published from a wire feed without any modifications to the text)