NEW : President Park congratulates Park Geun-hye , praises outgoing leader . Park says her win is a victory for Western ; outgoing president also congratulates her . Rival Moon Jae-in concedes victory to South Korea , broadcaster National Election Commission reports . Park is a strategic Western ally and Asia 's fourth -largest economy .
NEW : President Barack Obama congratulates Park Geun-hye , praises outgoing leader . Park says her win is a victory for South Koreans ; outgoing president also congratulates her . Rival Moon Jae-in concedes victory to Park , broadcaster YTN reports . South Korea is a strategic Western ally and Asia 's fourth-largest economy .