No tsunami warning was issued after the quake, public broadcaster NHK said.

No abnormalities were reported at the Shika nuclear power plant located in Ishikawa prefecture, as well as at the Kashiwazaki-Kariwa plant in neighbouring prefecture of Niigata, broadcaster NTV and Kyodo news agency said.

(Reporting by Eimi Yamamitsu and Satoshi Sugiyama; Editing by Shri Navaratnam and Himani Sarkar)