U.S. Secretary of State John Kerry (R) and visiting South Korean Minister of Foreign Affairs and Trade Yun Byung-se attend a joint press conference at the State Department in Washington D.C., capital of the United States, April 2, 2013. The two held their first talks on Tuesday as tensions persist on the Korean Peninsula. (Xinhua/Zhang Jun)

U.S. Secretary of State John Kerry (R) and visiting South Korean Minister of Foreign Affairs and Trade Yun Byung-se attend a joint press conference at the State Department in Washington D.C., capital of the United States, April 2, 2013. The two held their first talks on Tuesday as tensions persist on the Korean Peninsula. (Xinhua/Zhang Jun)

U.S. Secretary of State John Kerry (rear) and visiting South Korean Minister of Foreign Affairs and Trade Yun Byung-se attend a joint press conference at the State Department in Washington D.C., capital of the United States, April 2, 2013. The two held their first talks on Tuesday as tensions persist on the Korean Peninsula. (Xinhua/Zhang Jun)

U.S. Secretary of State John Kerry (R) and visiting South Korean Minister of Foreign Affairs and Trade Yun Byung-se attend a joint press conference at the State Department in Washington D.C., capital of the United States, April 2, 2013. The two held their first talks on Tuesday as tensions persist on the Korean Peninsula. (Xinhua/Zhang Jun)