North Korean leader Kim Jong Un threatened to use nuclear weapons and destroy South Korea permanently if provoked, state media reported Friday, after the South’s leader warned that Kim’s regime would collapse if he attempted to use nuclear arms.

The exchange of such rhetoric between the rival Koreas is nothing new, but the latest comments come during heightened animosities over the North’s recent disclosure of a nuclear facility and its continuation of missile tests. Next week, observers say North Korea's rubber-stamp parliament is expected to constitutionally declare a hostile “two-state” system on the Korean Peninsula to formally reject reconciliation with South Korea and codify new national borders.

During a visit to a special operation forces unit on Wednesday, Kim said his military “would use without hesitation all the offensive forces it possesses, including nuclear weapons,” if South Korea attempts to use armed forces encroaching upon the sovereignty of North Korea, according to the North’s official Korean Central News Agency.

“If such a situation comes, the permanent existence of Seoul and the Republic of Korea would be impossible,” Kim said, using South Korea’s official name.

Kim’s statement was a response to South Korean President Yoon Suk Yeol’s speech at his country’s Armed Forces Day on Tuesday. Unveiling South Korea’s most powerful Hyunmoo-5 ballistic missile and other conventional weapons that could target North Korea, Yoon said the day that North Korea tries to use nuclear weapons would be the end of the Kim government because Kim would face “the resolute and overwhelming response” of the South Korean-U.S. alliance.

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Kim responded that Yoon’s address fully betrayed his “bellicose temerity” and showed “the security uneasiness and irritating psychology of the puppet forces.”

In a derisive comment, Kim called Yoon "an abnormal man,” saying that “the puppet Yoon bragged about an overwhelming counteraction of military muscle at the doorstep of a state that possesses nuclear weapons.” On Thursday, Kim’s sister and senior official, Kim Yo Jong, also ridiculed South Korea's showcasing of the Hyunmoo-5 missile, saying there there’s no way for South Korea to counter the North Korea’s nuclear forces with conventional weapons.

Since adopting an escalatory nuclear doctrine in 2022, Kim has repeatedly threatened to use nuclear weapons preemptively. But many foreign experts say it's still unlikely that he would use his nuclear arms first because his military is outmatched by the U.S. and its allied forces. In July, South Korea and the U.S. signed a defense guideline on integrating South Korea's conventional capabilities with the U.S. nuclear forces to better deal with North Korea's advancing nuclear program. South Korea has no nuclear weapons.

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Animosities between the Koreas are at the worst point in years with Kim's provocative run of missile tests and the South Korean-U.S. military exercises intensifying in a cycle of tit-for-tat. All communication channels and exchange programs between the rivals remain stalled since 2019, when a broader U.S.-North Korea diplomacy on ending the North's nuclear program collapsed.

In January, Kim called for rewriting North Korea’s constitution to eliminate the idea of a peaceful unification between the war-divided countries and to cement the South as an “invariable principal enemy.”

He also reiterated that his country does not recognize the Northern Limit Line, a western sea boundary that was drawn by the U.S.-led U.N. Command at the end of the 1950-53 Korean War. He called for the new constitution to include a clear definition of the North’s territories. North Korea has traditionally insisted upon a boundary that encroaches deeply into waters currently controlled by South Korea.

Read more: North Korea's Kim vows to make his nuclear force ready for combat with US

On Friday, South Korea’s military said North Korea was again flying balloons likely carrying trash across the border into South Korea. Since late May, North Korea has launched thousands of rubbish-carrying balloons toward South Korea, prompting South Korea to resume anti-Pyongyang propaganda loudspeaker broadcasts at border areas.