A 7.9-magnitude earthquake has struck off the northeastern coast of Japan, triggering a six-metre tsunami warning.
The quake shook buildings in the capital,Tokyo, for several minutes on Friday, and sent people out onto the streets, witnesses reported.
Japan's NHK television showed black smoke billowing from a building in Odaiba, a suburb of Tokyo.
The country's meteorological agency warned that a tsunami as high as six metres could strike the coast near Miyagi prefecture, closest to the epicentre, and just a short time later broadcaster NHK said a tsunami of 50 cm had hit Japan's
northern coast.
NHK showed pictures of major tsunami damage in the north, with cars, trucks, houses and buildings being swept away in Onahama city in Fukushima prefecture.
Friday's quake struck at a depth of 10 kilometres, about 125 kilometres off the eastern coast, the meterological agency said.
Japan lies on the 'Ring of Fire'- an arc of earthquake and volcanic zones that stretches around the Pacific Rim and where about 90 per cent of the world's quakes occur.
Several earthquakes have hit the region in recent days, including a 7.2-magnitude quake on Wednesday.