TOKYO (REUTERS) - A magnitude 6.7 earthquake struck just off Japan's northernmost main island of Hokkaido on Thursday (Jan 14), Japan's Meteorological Agency said.

No tsunami warning was issued and NHK national television said that while there might be some changes in sea level, no tsunami damage was expected.

There were no immediate reports of damage.

On March 11, 2011, the north-east coast was struck by a magnitude 9.0 earthquake, the strongest quake in Japan on record, and a massive tsunami. Those events triggered the world's worst nuclear crisis since Chernobyl a quarter of a century earlier.