A volcano erupted in central Japan on Saturday, shooting ash and rocks into the air and leaving eight hikers reportedly injured.
The eruption of the 3,067-metre (10,121-foot) Mount Ontake happened around midday, the meteorological agency said.
Television footage showed huge clouds of smoke billowing from the summit of the peak, which is a popular destination for trekkers.
Japan's public broadcaster NHK said eight people were injured, while local authorities said they had received several unconfirmed reports of injuries to mountaineers.
"Details, including the number of the injured, remain unknown as we are still sorting out information," said an official of the Nagano prefecture fire department.
The meteorological agency forecast further eruptions of the mountain, warning that volcanic debris may fall within four kilometres (2.5 miles) of the peak.
The agency also placed restrictions on access to the mountain, while calling on local residents to remain on alert as an eruption could shatter windows miles away. (AFP)