An earthquake struck northeastern Japan on Saturday, hitting areas devastated by the 2011 disaster and generating a tsunami of 1 metre, public broadcaster NHK said.
The quake hit the coast of Miyagi Prefecture at 6:26 pm (0926 GMT) and had a magnitude of 7.2 at a depth of 60 km (40 miles), the Japan Meteorological Agency said.
NHK warned the public against going near the shore, reports Reuters.
Tokyo Electric Power said it had found no irregularities at its Fukushima Daiichi nuclear plant - wrecked by the massive March 2011 quake that caused nuclear meltdowns and mass evacuations. A spokesman said there were also no irregularities at its nearby Daini facility.
There were no irregularities at Tohoku Electric Power Co's Onagawa nuclear plant, the nuclear regulator said in an email.
Miyagi Prefecture was having power outages in some areas, according to the website of the Tohoku Electric Power Network.
NHK said service on the Tohoku shinkansen bullet train had been halted.
"It was a really bad, long shaking from side-to-side. It was even longer than the quake last month, but at least the building here is all right," Shizue Onodera told NHK from the shop where she works in the city of Ishinomaki.
"Lots of bottles smashed on the floor," she said. "The electricity is on."
NHK footage from inside its Sendai bureau showing a plaque suspended from the ceiling shaking for about 30 seconds following the tremor. It did not report any items falling from shelves or any immediate damage.
The quake could be felt in Tokyo about 400 km south of the epicentre.