A strong earthquake has struck off Japan's Bonin Islands, but officials say there is no danger of a tsunami.

The quake shook buildings in Tokyo on Saturday, setting off car alarms as it rattled the Japanese capital.

Residential buildings swayed for around a minute as the quake built in intensity at around 8.30pm (1130 GMT).

Japan's Meteorological Agency says the offshore earthquake struck Saturday at 8:24 p.m. at a depth of 590 kilometers (370 miles). The US Geological Survey says the quake had a magnitude of 7.8 and a depth of 678 kilometres.

Public broadcaster NHK said there were no immediate reports of injuries or damage.

The tremor was powerful enough to rattle most of Japan, from the southern islands of Okinawa to Hokkaido in the north. About 400 houses in Saitama prefecture, just north of the capital, were without power, according to the Tokyo Electric Power Company.

The Bonin islands are about 1,000 kilometers (620 miles) south of Tokyo.

The meteorological agency did not issue a tsunami warning because the quake struck so far beneath the earth's surface.

In March 2011, a magnitude 9.0 earthquake rocked northeastern Japan, triggering a tsunami that killed more than 18,500 people and ravaged much of the northern Pacific coast.

The depth of that quake was just 24km, according to the meteorological agency.