This move came after Acting President, Prime Minister Han Duck-soo and Deputy Prime Minister for Economic Affairs Choi Sang-mok successively resigned on Thursday to run in the presidential election scheduled for June 3.

South Korea's new acting President Lee on Friday instructed the military to raise its readiness posture to the "highest level," and called for thorough preparations to ensure the June 3 presidential election will proceed in an "orderly" and "fair" manner.

He instructed Foreign Minister Cho Tae-yul to cooperate closely with key friendly nations to maintain international trust in South Korea.