Some passengers are waiting for the subway to resume operation. (Photo: Xinhua)

    TOKYO, July 23 (Xinhuanet) -- An earthquake measuring 5.7 on the Richter scale struck Tokyo and its surrounding area Saturday, but caused no major damage.

    The earthquake at 4:35 p.m. (0735 GMT) produced no tsunami warning.

    The strongest intensity registered at upper 5 in one of Tokyo's23 wards, according the Japan Meteorological Agency. Japan's seismic intensity scale tops at seven.

    The focus of the quake was 70 kilometers underground in Tokyo's neighboring Chiba Prefecture, the agency said.

    So far, there has been no reports of casualties or major damages.

    Narita Airport resumed operation after a brief closing. However, Tokyo's subway system and railways are still in suspension.

    No damage to electric power facilities has been reported, according to Tokyo Electric Power Co.

    Japan has been hit by numerous quakes since an earthquake measuring 6.8 on the Richter scale struck Ojiya, Niigata Prefecture, 200 kilometers northwest of Tokyo, on Oct. 23 last year, which claimed the lives of 40 people. On July 10 this year, an earthquake measuring 5.8 on the Richter scale rocked sea watersnear Izu Islquands, about 270 km southeast of Tokyo. Enditem