 North Korea denounced the abrogation of paragraph 13(d) as an attempt to wreck the armistice agreement and turn Korea into a U.S. atomic warfare zone.At the U.N. General Assembly in November 1957, the Soviet Union and Czechoslovakia condemned the decision of the United Nations Command to introduce nuclear weapons into Korea.North Korea responded militarily by digging massive underground fortifications, and forwarded deployment of its conventional forces for a possible counterattack against the United States forces stationed in South Korea.