At least nine people have been injured in a volcanic eruption near a ski resort in central Japan, officials said.

Most of the injured were on the ski slopes, while some were in a gondola where glass was broken apparently by a flying rock, said Makoto Shinohara, an official in Kusatsu town.

Five people had broken bones, but none of the injuries were life-threatening.

The Japanese military said six soldiers who were among about 30 on ski training were buried by a nearby avalanche, but they were all rescued.

The Japan Meteorological Agency says snow-covered Mount Kusatsu-Shirane erupted around 10am.