A volcano in central Japan has erupted, sending ash clouds down the mountains slope for more than 3 kilometers. At least one person has died and 70 were injured, while aircraft have been forced to divert to avoid the dangerous area.

Medics confirmed the death of at least one person, while 70 more were reported to be injured, NHK reported. Thirty of the injured have been sent to hospital in critical condition, health officials added.

The Ontake volcano on the border of Nagano and Gifu prefectures, 200 kilometers west of Tokyo, started erupting at about 11:53 local time (02:53 GMT), NHK reported, citing Japans Meteorological Agency.

NHK released a video showing the volcano spewing thick, gray smoke into the air.

More than 250 people were left stranded near the top of the volcano, police told NHK, adding that one hiker was rescued after being buried in ash near the volcano. He remains unconscious.

Japans Meteorological Agency declared a level 3 volcano alert on a 1 to 5 scale, which means people are advised to stay away from the mountain. The agency warned that the debris from the volcano could fall as far as 4 kilometers away.