An earthquake with a preliminary magnitude of 7.3 struck northeastern Japan's Fukushima on Tuesday, a weather agency said.
The quake registered lower five on the Japanese seismic scale of seven in northeastern Fukushima prefecture, Xinhua quoted the Japan Meteorological Agency as saying.
The epicentre of the quake was at a latitude of 37.3 degrees north and a longitude of 141.6 degrees east and occurred at depth of 60km, said the agency.
The temblor was centred in offshore of northeastern Fukushima prefecture which borders the Pacific Ocean and is to the northeast of the nation's capital city of Tokyo.
Three-meter tsunami warning was issued and so far no major damage or injuries were reported.