A strong earthquake struck off the coast of Fukushima, Japan, on Saturday, just weeks before the 10-year anniversary of the deadly 2011 tsunami.
The 7.3-magnitude quake was felt strongly in Tokyo, but a tsunami warning has not been issued.
There are reports of about 50 people injured, officials say, and almost one million homes are without power.
The quake struck near the epicentre of a 2011 earthquake which triggered a tsunami and killed over 18,000 people.
That tsunami caused a nuclear accident at the Fukushima Daiichi Nuclear Power Plant – the world’s most severe nuclear accident since the Chernobyl disaster in 1986.
Japan’s meteorological agency (JMA) said Saturday’s earthquake was believed to be an aftershock of the massive 2011 quake. Aftershocks after a large earthquake can continue over a period of many years.
Saturday’s quake hit at 23:08 local time (14:08 GMT) at a depth of 60km (37 miles) in the Pacific, off Japan’s eastern coast, JMA said. Aftershocks have continued to hit the region since.
Chief Cabinet Secretary Katsunobu Kato told reporters that evaluations were under way, including of the region’s nuclear plants.
“Casualties and structural damage are being assessed,” he told a press conference, but added that parts of the high-speed bullet train network had been suspended because of power outages.
“Surveys are being done at Fukushima Daiichi nuclear pant… We have received reports that Onagawa nuclear plant and Fukushima Daichi nuclear plant are not showing any abnormality.”
Fukushima nuclear plant operator Tepco also tweeted that there were “currently no abnormalities” found at its plants.
Despite reassurances from officials, many residents on the coast are evacuating their homes and heading for higher ground, Japanese news agency Kyodo reports.
“”Even if people say we don’t need to worry about a tsunami, I won’t buy it,” one 50-year-old man told the publication. “I learned from my bitter experience 10 years ago, and that’s why I evacuated.”