The two Koreas are ratcheting up their cross-border rhetoric to new heights with threats of nuclear retaliation and regime annihilation, raising concerns that a minor border incident could turn brinkmanship into an armed clash.    

Bilateral tensions have been bubbling for decades, but appear to have ramped up once more since the right-of-center President Yoon Suk Yeol took office in Seoul in 2022, replacing the left-leaning administration of former president Moon Jae-in and his policy of outreach to Pyongyang.  

With the relationship worsening, Yoon provoked fury in the North on October 1 when he gave a speech at South Korea's Armed Forces Day, warning North Korean leader Kim Jong Un that he would face "the end of his regime" if Pyongyang ever attempted to use nuclear weapons.

He insisted that there would be a "resolute and overwhelming" reaction from the South and its US allies. 

Yoon's warning came a little over a week after Kim Yo-jong, the influential sister of the North Korean leader, insisted that the regime would "continuously and limitlessly" expand and enhance its nuclear deterrent against what she claimed were US threats, pointing to the arrival of the nuclear-powered submarine USS Vermont in the South Korean port of Busan.  

South Korean firepower on display

The display of South Korean firepower at Armed Forces Day included the latest missile system in the South's armory, the Hyunmoo-5, while the US commitment to the security of the South was underlined by a flyover by a nuclear-capable US B1-bomber. 

Kim Jong Un responded by calling Yoon a "puppet" of the US and insisting that the North would use nuclear weapons "without hesitation" if the South or the US attempted to use force against Pyongyang.

The North Korean leader threw in a calculated insult for good measure, describing his counterpart as an "abnormal man."

Kim Seong-kyung, a professor of North Korean society and culture at the University of North Korean Studies in Seoul, said the present situation is "really worrying."

"In previous years the two sides would be vocal and provocative as they threatened each other, but the North clearly has a nuclear capability and they are now threatening to use it," she told DW.  

"Much has changed since Kim altered the North's constitution to define the South as a hostile country, to state there are no special bilateral relations and to rule out the previous aims for reunification."

Threatening to use a nuclear weapon and actually going through with such a dramatic and escalatory action are quite different things, the expert pointed out.

While Pyongyang is still reined in by the virtual certainty that the retaliatory strikes would be devastating to the North Korean regime, there is concern that in the current situation where there is sharp rhetoric and no communication between the two sides, even a minor border incident or a misunderstanding could quickly escalate.

Impact on the US election 

Kim Seong-kyung also sees the North's threats as a message in part to the US, less than one month ahead of a pivotal election that could have far-reaching implications for South Korea should an isolationist administration take office early next year.  

"They are targeting the US with these words, although North Korea is not really a priority issue in the election," she said. "Kim Jong Un is trying to make noise so that if [Donald] Trump wins, there is a possibility that he might again agree to talks." 

In a recent interview with Radio Free Asia, John Bolton, Trump's former top security adviser, said Kim would be hoping that Trump regains the White House as he offers a far greater possibility of engaging with and legitimizing the North Korean regime than a Kamala Harris administration.  

'Intimidating and sobering'

Dan Pinkston, a professor of international relations at the Seoul campus of Troy University, said that while the rhetoric was increasing, there have actually been fewer full-blooded clashes on the border in the 12 years since Kim Jong Un took power compared to previous periods in the troubled neighbors' relationship.  

"But while there have not been so many kinetic acts occurring, it is also clear that the North has dramatically accelerated its development of weapons of mass destruction and the missiles it needs to deliver them," he told DW. 

"The potential of the weapons that they now have at their fingertips is both intimidating and sobering," he said.  

The value of those weapons lies in their deterrent capability and, for the North, convincing the South and the US that Pyongyang is willing to use them. And that is the reason why Kim and his sister are making such strident claims about their readiness to press the button, he suggested.  

Edited by: Srinivas Mazumdaru