A violent volcanic eruption in Japan forced the evacuation of an island on Friday, as a huge column of ash was shot high into the sky.

Footage by the Japan Meteorological Agency captured the moment the plume rocketed from Mount Shindake on the far southern island of Kuchinoerabu.

The black cloud reached as high as 9,000 metres (29,500 feet), the agency said, and was accompanied by a five-minute volcanic quake.

Television pictures showed the after-effects of the pyroclastic flow, which had cascaded down the mountainside towards one of the island's harbours.

Grey ash blanketed the breakwaters and discoloured the sea.

The volcano continued to belch steam throughout the day as a dusting of white ash settled on mountain peaks, giving them a winter-like appearance.

The Fire and Disaster Management Agency said it had accounted for all of the nearly 140 inhabitants, with one elderly man having suffered a minor facial injury and another feeling nauseous.

Residents were evacuated to a nearby island aboard coastguard boats and a ferry, officials said.

A woman who was taken by helicopter told reporters the eruption had been frighteningly powerful.

"The sky turned completely dark and there was a thunderous roar and then I heard a boom," she said.

Community leader Nobuaki Hayashi told public broadcaster NHK how the eruption, which came around 10:00 am (0100 GMT) had blocked out the morning light.

"Dark smoke rose quite high, I couldn't tell how high. But it became dark outside," he told the network.

The volcano has been under observation since an eruption last year, with a two-kilometre (one-mile) exclusion zone in force, but volcanologists on Friday rapidly raised the alert level to five -- the highest on the scale -- triggering the evacuation order.

- More eruptions possible -

"A volcanic eruption occurred at Shindake at 9:59 am. Along with this eruption, a pyroclastic flow reached the coastline" of the island, the weather agency said.

Sadayuki Kitagawa, director of the volcanology division at the agency, warned the danger was not over.

"It's possible that eruptions of a similar scale could happen in the future. We are warning residents about pyroclastic flows, and asking people to obey evacuation instructions," he told a briefing.

Japan sits at the junction of several of the Earth's tectonic plates and the country is dotted with active volcanoes.

Any eruption is big news, and sends the nation's emergency response organs into a flurry of activity.

Prime Minister Shinzo Abe said he had mobilised "all functions of government" to ensure the safety of residents, including coastguard boats and military helicopters.

"I ordered authorities to swiftly gather information on damage, ensure local residents' safety through evacuations, and boost observation of the volcano," he told reporters.

Kagoshima prefecture, in which Kuchinoerabu sits, said it had requested the military send troops to help with disaster relief.

Major carriers Japan Airlines and All Nippon Airways said there had been no immediate impact on flights.

Eruptions at Shindake have been recorded for nearly two centuries, with the last significant period of activity from 1966 to 1980.

Volcano expert Kazuhiro Ishihara, professor emeritus at Kyoto University, told NHK that evacuation managers would be taking account of cinders and wind direction in deciding how to proceed.

"The eruption could continue for some time given the mountain's history," he said.

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