Eds: Adds details, nuclear plant situations (previous news was posted at 13:34)
A magnitude-7.1 earthquake struck eastern Japan Monday afternoon and a tsunami warning was issued for the coast of Ibaraki prefecture, broadcaster NHK reported.
There was no immediate impact reported at the stricken Fukushima Daiichi nuclear power plant, officials at the plant operator Tokyo Electric Power Co said, DPA reported.
The company instructed workers to leave the site temporarily.
There were no immediate reports of casualties or property damage.
Tsunami waves as high as 1 metre was expected to have already reached the coast of Ibaraki, NHK reported.
The same region was hit by a magnitude-9 quake and tsunami on March 11.
Monday's quake occurred at 5:16 pm (0816 GMT), with an epicentre off the coast of Fukushima prefecture, the Meteorological Agency said.
Strong earthquake hits eastern Japan, tsunami warning (UPDATE)
A magnitude-7.1 earthquake struck eastern Japan Monday afternoon and a tsunami warning was issued for the coast of Ibaraki prefecture, broadcaster NHK reported.
