Kim Yo-chen, the powerful sister of North Korea's leader Kim Jong-un criticized the presence of an American nuclear submarine in the South Korean port of Pusan, reports "Reuters".
She described this as evidence of US ambition to "bring out its nuclear strategic assets, show its power and increase its threats".
Yesterday, the South Korean Navy said the submarine USS Vermont had arrived at the Pusan Naval Base to replenish supplies and allow crew members to rest.
Kim's statement comes after the foreign ministers of South Korea, the United States and Japan held a meeting on the sidelines of the United Nations General Assembly yesterday.
They expressed concern about the recent disclosure of North Korea's uranium enrichment facilities and the ongoing "illegal" military cooperation with Russia and agreed to work towards the realization of a trilateral summit this year.