An earthquake with a preliminary magnitude of 5.0 jolted Japan's Kanto and northeastern regions Friday, said the Japan Meteorological Agency.

The focus of the quake, which occurred at 10:28 a.m. (0128 GMT), was located some 40 km under the sea off Ibaraki Prefecture, said the agency.

There were no immediate reports of casualties or damage to properties, and no tsunami warning was issued.