TOKYO • One man was killed and at least 11 people injured when rocks from an erupting volcano rained down on skiers at a mountain resort in central Japan yesterday and an avalanche soon after the eruption engulfed about a dozen skiers.

Six of those trapped were members of Japan's Ground Self-defence Force engaged in winter training manoeuvres, Defence Minister Itsunori Onodera said.

All were rescued but most were injured and one of them later died, the Defence Ministry said.

Japanese media reported that many of the injured were apparently hit by volcanic rocks. Two were critically injured and three seriously, national broadcaster NHK said.

Kusatsu-Shirane, a 2,160m volcano, erupted yesterday morning, the Japanese Meteorological Agency (JMA) said. The agency warned that further eruptions could not be ruled out and that rocks could be thrown as far as 2km from the peak.

Video footage showed skiers gliding down the slopes as black rocks plummeted from the skies and snow billowed up as they struck the ground, sometimes just missing skiers. A cloud of black smoke later drifted in.

"There was this huge boom and a big plume of totally black smoke rose up," one skier told NHK. "I had absolutely no idea what had happened." A photograph taken at the site and shown on NHK depicted a gondola with a shattered window.

The ski resort temporarily lost power, leaving a number of skiers suspended in gondolas for around half an hour. Around 80 skiers in a hut at the top of the mountain were awaiting rescue yesterday afternoon.

The warning level for the peak was raised to 3, meaning that people should not climb the mountain, the JMA said.

Japan has 110 active volcanoes and monitors 47 of them around the clock. In September 2014, 63 people were killed on Mount Ontake, the worst volcanic disaster in Japan for nearly 90 years.

Meanwhile in Tokyo, a rare heavy blanket of snow on Monday left thousands of travellers stranded and scores injured.

Japan's weather agency recorded as much as 23cm of snow in some parts of Tokyo, the biggest snowfall since February 2014.

NHK said at least 180 people had sustained minor injuries on the frozen streets and there had been around 700 traffic accidents. Domestic and international flights departing from and arriving at the Japanese capital were scrapped due to the snow, leaving more than 9,000 people stranded overnight at Narita airport, officials said.

AGENCE FRANCE-PRESSE, REUTERS