An earthquake with a preliminary magnitude of 7.2 on the Richter scale hit Japan's northeastern region Wednesday, said the Japan Meteorological Agency, which issued a tsunami warning.

The focus of the quake, which occurred at around 11:45 a.m. ( 0245 GMT), was located 10 km under the sea east of Miyagi Prefecture, said the agency.

There were no immediate reports of casualties or damage to properties.