An earthquake measuring 6.7 on the Richter scale on Thursday rocked the northeastern Honshu island of Japan, said the Japan Meteorological Agency.

The focus of the quake, which occurred at 6:51 a.m. local time (2151 GMT), was located some 20 km under the sea off Iwate and Aomori Prefecture, said the agency.

A tsunami advisory with expected waves up to 50 centimeters was issued for the Pacific coast of Iwate Prefecture. The warning was lifted at around 7:47 a.m. local time (2247 GMT).

There were no immediate reports of casualties or damage to properties, and the high-speed Shinkansen operation has not be disrupted. No abnormalities has been observed at a nearby nuclear plant in Aomori, NHK said.