By Yoshifumi Takemoto TOKYO (Reuters) - Japan is likely to extend by two weeks or more coronavirus containment measures in the greater Tokyo area, four government sources said on Thursday, as infection numbers creep up less than a month before the Summer Olympics start. Japan's capital and three neighbouring prefectures are among areas under a 'quasi' state of emergency set to run through July 11, but a recent uptick in infections has officials leaning towards keeping restrictions in place - a move that could affect the number of spectators allowed into Olympic venues, the sources said. Depend...