An earthquake with a magnitude of 6.0 struck off the coast ofTokyo early Monday, jolting central districts in the Japanese capital, but no tsunamialert was issued, (Kyodo) news agency reported citing the Japan MeteorologicalAgency.The quake originated around 162 kilometers underground near Izu Oshima Islandin the Pacific Ocean some 120 km south of Tokyo, the agency said.It revised the estimated magnitude from an earlier announced 6.2.