An earthquake measuring 5.5 on the Richter scale on Sunday rocked Ibaraki Prefecture and its vicinity in Japan's Kanto region in eastern Honshu island, said the Japan Meteorological Agency. No tsunami warning has been issued.

The focus of the quake, which occurred at 10:23 a.m. local time (0123 GMT), was at a depth of some 10 km in northern Ibaraki, said the agency.

The quake was most strongly felt in Hitachi city in the prefecture. It was also felt in neighboring Fukushima Prefecture and Tokyo metropolitan area.

There were no immediate reports of abnormalities to the crippled Fukushima No.1 nuclear plant, or casualties or damage to properties.