Japan's Premier Yukio Hatoyama will sack a coalition partner, Social Democrats leader and consumer affairs minister Mizuho Fukushima, for opposing a US base deal, broadcaster NHK reported Friday. The left-leaning and pacifist cabinet minister had refused to support an agreement with Washington announced Friday to keep a controversial US airbase on the southern island of Okinawa, where locals vehemently oppose it. The premier's reported move would throw into turmoil Japan's young centre-left coalition government, although it would retain a majority in both houses of parliament even if the Social Democrats bolt the ruling coalition. Upper house elections are expected on July 11. 