TOKYO, March 23 (Xinhua) -- An earthquake with a preliminary magnitude of 4.1 rocked southern Japan's Kumamoto prefecture late on Friday, Japan Meteorological Agency said.

    The 10:37 p.m. (1337 GMT) quake measured 4 on the Japanese seismic intensity scale of 7 in the prefecture, the agency said, adding that focus of the quake, which is in Kumamoto city, Kumamoto prefecture, was shallow.

    No tsunami warning was issued. There was no immediate report as to casualty or damages as to the quake.

    When seismic intensity reaches scale 4, indoor hanging objects swing considerably, and electric wires swing considerably, according to the agency.