The quake in the Pacific Ocean took place at 2007 GMT, about 170 km southwest of Tokyo, the USGS said. No tsunami watch was issued.

The quake was felt in Japan's central province of Shizuoka, but there were no early reports of damage or injuries. The epicentre was about 20 km below the seabed.

On Sunday, a 6.9-magnitude quake shook Tokyo and surrounding areas.

In December 2004, an earthquake at sea generated a massive tsunami that hit the shores along the Indian Ocean, leaving 230,000 people, mostly in Indonesia, dead.