An earthquake measuring 5.6 on the Richter scale on Monday hit Fukushima Prefecture and its vicinity in northeast Japan, said the Japan Meteorological Agency. The focus of the quake, which occurred at 11:46 a.m. local time (0246 GMT), was located some 50 km under the sea off Fukushima, said the agency. There were no immediate reports of casualties or damage to properties, and no tsunami warning was issued.