A earthquake with a preliminary magnitude of 6.7 jolted eastern Japan today, and was felt over a wide area, including in Tokyo, Japan's meteorological agency said.
The quake, at 1.45 am (1645 GMT), was centred in the Pacific Ocean east of Tokyo.
There were no immediate reports of injuries or damage after the quake, which measured 5 on the Japanese scale of 7 in some parts northeast of Tokyo, NHK said.
No tsunami damage was expected from the quake but there may be slight sea level changes, the agency said on its website.