Workers were evacuated from two nuclear plants yesterday as Japan was rattled by a strong aftershock and tsunami warning.
It came nearly a month after the huge earthquake and tsunami that devastated the country's north-east coast and is thought to have killed 25,000 people.
Officials at the damaged Fukushima Dai-ichi nuclear plant said there were no signs of new problems caused by the aftershock, that measured 7.1-magnitude.
Plant operator Tokyo Electric Power Co evacuated two workers there and seven at a sister plant to the south that was not badly damaged. The public broadcaster NHK told coastal residents to move to higher ground and away from the shore after the quake.
The Japan meteorological agency issued a tsunami warning which was later cancelled.
Officials say yesterday's aftershock hit 16 miles under the water, off Miyagi prefecture. The quake that preceded last month's tsunami was a 9.0-magnitude.