An earthquake struck off the coast of northeastern Japan on Saturday, shaking buildings and generating a tsunami of 1 metre in the same area devastated a decade ago by a quake and tsunami.
The earthquake, with a magnitude of 7.2, hit off the coast of Miyagi Prefecture at 6:26 p.m. (0926 GMT) at a depth of 60 km (40 miles), the Japan Meteorological Agency said.
While there were no immediate reports of deaths or injuries, the quake was strong enough to shake buildings in Tokyo, some 400 km (250 miles) away.
An official for the meteorological agency told reporters it was an aftershock of the deadly 2011 quake. The 2011 disaster, one of the strongest earthquakes on record, is still generating aftershocks a decade later, experts have said. A magnitude 7.3 quake last month had also been deemed to be an aftershock.
About an hour after Saturday's quake, all tsunami alerts were lifted, broadcaster NHK said, after warning the public not to go near the shore.
"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."
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.
Service on the Tohoku shinkansen bullet train was halted, NHK said.
About 200 households in Kurihara city, Miyagi Prefecture, lost power because of the quake, the trade and industry ministry said.
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.