Various analysts had expressed concern that North Korea was on the cusp of launching its third nuclear test following a failed rocket launch in April. That effort ended a deal with the United States for food assistance in exchange for a moratorium on nuclear work.
Pyongyang said Wednesday that Washington was in no place to criticize its defense systems given its strategic relationship with South Korea, the Yonhap News Agency reports.
Missile deals with South Korea, the agency reported, would "result in endangering the security of the U.S. mainland, far from ensuring it."
Last week, the South Korean and U.S. governments agreed to extend the range of South Korean missiles to more than twice their current range of 500 miles.
Pyongyang said this week that has the technology to strike the U.S. mainland and its strategic interests in the region.
Tensions on the Korean Peninsula are high in the wake of the December death of North Korean leader Kim Kong Il.