Image copyright NIPPON HOSO KYOKAI

Authorities in Japan have warned people of the risk of large flying rocks within 4km (2.5 miles) of an erupting volcano on Kyushu island.

Mount Shinmoedake has been spewing ash for days but eruptions turned explosive very early on Saturday.

Volcanic activity there could continue for several months, experts say.

In the 1967 James Bond film You Only Live Twice, Mount Shinmoedake was used to depict the exterior of a criminal organisation's secret lair.

On Saturday the country's meteorological agency issued new warnings, saying flying rocks could now be expected to reach a 4km radius around the volcano.

Image copyright Nippon Hoso Kyokai Image caption People living in the area are wearing helmets to protect against the ash and potential falling rocks

Image copyright Reuters Image caption Aerial photos have shown the intensity of the peak's eruption

The Japanese Meteorological Agency (JMA) said large explosions happened at 01:54 local time (16:54 GMT on Friday) and at 04:27 local time.

Smoke rose 4,500m (15,000ft) in the air.

Vibrations have caused nearby buildings to shake, and lava is running down one side of the volcano.

An eruption in 2011 caused hundreds of people to leave their homes.

Japan has 110 active volcanoes.