North Korea opposes war but would use nuclear weapons if South Korea attacked, Kim Yo Jong, the all-powerful sister of leader Kim Jong Un, said on Tuesday.

Kim Yo Jong, who is a senior official in the government, said it was a "very big mistake" for South Korea's minister of defence to make recent remarks about his country’s missiles having the capability to hit targets in North Korea, state news agency KCNA reported.

Kim's criticisms are most likely aimed at South Korean President-elect Yoon Suk-yeol, who has called for a more muscular defence against North Korean threats, a Reuters report cited Rachel Minyoung Lee, an analyst with the U.S.-based 38 North project as saying.

Both Koreas have stepped up displays of military might after North Korea test-fired a series of powerful missiles this year. Officials in Seoul and Washington also fear it may be preparing to resume testing nuclear weapons for the first time since 2017 amid stalled negotiations.

Kim and another North Korean official issued earlier statements on Sunday condemning Suh's remarks, and warned that Pyongyang would destroy major targets in Seoul if the South takes any "dangerous military action" such as a pre-emptive strike.

The statements suggest Pyongyang is preparing the North Korean public for a possible shift in inter-Korean relations once Yoon takes office in May, Lee added.

Meanwhile, a delegation from Yoon's team was in Washington this week to meet with U.S. officials, who reiterated their commitment to defending South Korea, according to a statement by the U.S. State Department on Tuesday.

In her statement on Tuesday, Kim said, If the South Korean military violates North Korea territory, it will face an "unimaginably terrible disaster" as the North's nuclear combat force will have to carry out its duty, she said.

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