A powerful earthquake has hit northern Japan, triggering a tsunami warning and plunging more than two million homes in Tokyo into darkness.
The tremor registered a magnitude of 7.3, according to public broadcaster NHK.
The Japan Meteorological Agency said the quake struck 60km (36 miles) below the sea off the coast of Fukushima.
It is the same region which was devastated by a magnitude 9.0 quake in March 2011, causing a tsunami which led to an accident at the Fukushima nuclear plant.
There are no immediate reports of casualties.
There have been widespread power outages in the capital of Tokyo, which is situated around 150 miles away from Fukushima.
Tokyo Electric Power Company said that around two million households were without power and that it was also checking the condition of reactors at the Fukushima plant, NHK said.
Authorities had warned residents in Fukushima, Miyagi and Yamagata prefectures to expect aftershocks.
Prime Minister Fumio Kishida said the government was assessing the extent of any damage following the tremor.