A strong earthquake with a preliminary magnitude of 7.1 hit off the coast of eastern Japan on Saturday, shaking buildings and triggering widespread blackouts, but there appeared to be no major damage and no tsunami warning was issued.

The epicentre of the earthquake was off the coast of Fukushima prefecture at a depth of 60km, the Japan Meteorological Agency said.

The earthquake, which hit at 11:08pm local time (1408 GMT), and shook buildings in the capital Tokyo and elsewhere. The Meteorological Agency said no tsunami warning had been issued.

At least two dozen people were injured, according to reports from the Kyodo news agency. About 950,000 households were without power, government spokesman Katsunobu Kato told a briefing carried on public broadcaster NHK. He said there were no irregularities at two nuclear facilities, Fukushima Dai-ni and Onagawa.

NHK said there were no reports of irregularities at another nuclear facility at Tokaimura. The quake hit near Fukushima just weeks before the 10-year anniversary of the March 11, 2011, quake that devastated northeast Japan and triggered a massive tsunami that led to the world’s worst nuclear crisis in a quarter of a century.