Explosive eruptions at a volcano featured in a James Bond film have prompted authorities in Japan to issue heightened warnings of flying rocks within 2.5 miles of the crater.

Increasing the alert to level three following two huge blasts at Mount Shinmoedake, the Japan Meteorological Agency said that rocks more than 50cm wide could be hurled from the volcano, which was used in You Only Live Twice as the exterior of the villain Blofeld’s secret rocket base.

Molten lava was seen running down one side of the crater.

One of Japan’s most dangerous volcanoes, Shinmoedake has been shooting ash and smoke into the air for five days, restricting entry to the 4,660ft mountain and causing the cancellation of flights from the nearby Kagoshima airport.

Residents living nearby were also warned about pyroclastic flows – hot gas and volcanic debris that race down the slopes at high speeds, incinerating or vaporising everything in their path.

Japan has 110 active volcanoes and the alerts range from level two, “Do not approach the crater”, to level five, “Evacuate”.

In January a soldier was killed and at least 11 injured after an eruption at Kusatsu-Shirane.