Concerns are rising that Japan could be hit by another massive earthquake after a magnitude-7.3 quake struck off the coast of northeastern Japan on Friday.
The quake struck in the same region that was battered by last year's massive earthquake and tsunami that triggered the Fukushima nuclear crisis.
High-rise buildings in Tokyo swayed for minutes during Friday's quake and at least two people were injured.
Japan's Asahi Shimbun reports that aftershocks could continue and warned residents in the northeastern region to exercise caution.
Japan's Defense Science and Technology Institute says the latest tremor is especially alarming, adding an earthquake with a magnitude of eight or over could soon strike the country.