On April 22, Seoul and Washington signed a deal to replace a previous accord that regulated the relations between the two states on the peaceful use of nuclear energy, along with the nine additional agreements.
"New [nuclear] Agreement in accordance with the diplomatic notes exchanged between our two countries has entered into force today," the statement said.
Relations between the United States and South Korea have been highly cooperative since 1950, when Washington supported Seoul during the Korean War. During the following decades, South Korea reduced its dependency on the United States and saw marked economic growth. Relations between the two countries were reaffirmed after conservative President Lee Myung-Bak assumed office in 2008. South Korea is designated a major non-NATO ally by the United States.