The operator of the Fukushima nuclear plant has ordered workers near the coast to move to higher ground after a 7.6 magnitude earthquake, Japanese broadcaster NHK reported.
Japan's emergency agencies have declared a tsunami warning for the region that includes the crippled nuclear site.
All but two of Japan's 50 reactors have been offline since a magnitude-9.0 earthquake in March 2011 triggered a tsunami which led to massive radiation leaks at the plant 160 miles northeast of Tokyo.
More top news
Weather set to stay cool and cloudy tomorrow
The multi-millionaire strip-club owner defended his policy of taking 23% of the service charges made by waitresses in his bars.
Eleven years after her arrival at Animal Lifeline centre in Staffordshire, Maggie is still waiting for a new owner.