Kim Yo Jong, the sister of North Korea's leader Kim Jong Un, says the launch last week of an intercontinental ballistic missile was just the beginning of the country's military offensive.

Kim issued a statement through the state-run Korean Central News Agency on Monday. This appeared to be in response to recent remarks by US National Security Advisor Jake Sullivan. He said in an interview that aired on Sunday that the US is ready for diplomacy, but that North Korea is not.

Kim's remarks in the statement, however, suggested that Pyongyang is not ready to sit down with Washington. She said it's a "daydream" for the US to think that it can "achieve irreversible disarmament" through such measures as a temporary halt to joint military exercises and relieving sanctions.

North Korea launched the new intercontinental ballistic missile Hwasong-18 last Wednesday. Kim said what the US witnessed a few days ago was just the beginning of North Korea's "already-launched" military offensive.

North Korea is set to mark the 70th anniversary of the 1953 Korean War Armistice on July 27. Pyongyang sees it as a day to celebrate what it calls its victory over the US.