Japan rates quake less serious than 3 Mile Island, Chernobyl

March 13 (Reuters) - A nuclear accident in Japan on Saturday rates as less serious than both the Three Mile Island accident in 1979 and the 1986 Chernobyl nuclear disaster, Japan's nuclear safety agency said.

An official at the agency said it has rated the incident at Tokyo Electric Power's nuclear plant north of Tokyo a 4 according to the International Nuclear and Radiological Event Scale (INES) .

Three Mile Island was rated 5 while Chernobyl was rated 7 on the 1 to 7 scale, the official said.

(Reporting by Risa Maeda; Editing by Nathan Layne)