A minor tsunami has hit the coast of northern Japan following a 6.8 undersea earthquake two hours ago.
A wave of 10 centimetres was monitored on the shore of Miyako, in eastern Iwate prefecture, after the Japanese meteorological agency had warned a tsunami of up to one metre was on the way.
The agency had earlier recorded the quake as 6.9, which struck the main island of Honshu.
An evacuation warning had been issued for coastal towns in north eastern Japan, and the city of Ofunato in Iwate issued an evacuation advisory to more than 1,350 households.
The quake struck at 8.06 am in the Pacific some 210 kilometres east of Miyako at a depth of 10 kilometres, the Japan meteorological agency said.
There were no immediate reports of injuries or casualties following the quake, local media said.
Tohoku Electric Power Co, which operates the Onagawa and Higashidori nuclear plants in nearby Miyagi and Aomori prefectures, said it saw no irregularities at the facilities after the quake.
Unlisted Japan Nuclear Fuel Ltd also said there were no irregularities recorded at its nuclear fuel reprocessing facility or other plants in Aomori.
All 48 of Japan's nuclear reactors remain offline after a March 2011 earthquake and tsunami, which triggered the Fukushima nuclear disaster in northeastern Japan.
Japan is hit by around a fifth of the world's powerful quakes every year and sits at the conjunction of several tectonic plates.
The Pacific Tsunami Warning Center in Hawaii said there was no danger of a Pacific-wide tsunami.
- Reuters, AFP
