South Korea and the United States are bracing for a possible North Korean nuclear test amid heightened tensions after this week's warning from Pyongyang that it is prepared to use nuclear weapons against its southern neighbor.
A nuclear test would be North Korea's first since 2017, ending a self-imposed moratorium. Experts say that, combined with recent belligerent rhetoric from the North, is likely to push the Biden administration and the government of incoming South Korean President Yoon Suk-yeol to take a tougher stance on Pyongyang.
Kim Yo Jong, the sister of North Korean leader Kim Jong Un and vice department director of the Central Committee of the Workers' Party of Korea, ratcheted up the tension with widely reported remarks on Tuesday. "In case South Korea opts for military confrontation with us, our nuclear combat force will have to inevitably carry out its duty," she said.
Kim Yo Jong serves as North Korea's mouthpiece for lashing out against South Korea and the United States.
Her warning came after a series of missile tests that began on January 5, including the latest launch on March 24 of an intercontinental ballistic missile capable of reaching the U.S.
During a press call Wednesday, Sung Kim, U.S. special representative for North Korea, said he was reluctant to speculate about any further launch by the North. "But I think it could be another missile launch. It could be a nuclear test."
Sydney Seiler, national intelligence officer for North Korea at the National Intelligence Council, described Kim Yo Jong's remarks as a "short-term choreography" during a webinar hosted Thursday by the Center for Strategic and International Studies, according to Yonhap News Agency. "North Korea will want to create an environment of tension and exploit our concerns about escalation," Seiler said.
Evans Revere, a former State Department official with extensive negotiating experience with North Korea, said, "I think people in Washington understand very clearly that North Korea has no intention of turning back from the path that it's on."
"A tougher, firmer and even clearer approach by the Biden administration [is likely] in the coming weeks and months as North Korea continues to ramp up its ballistic missile and nuclear capabilities," Revere said.
Harry Kazianis, senior director of Korean studies at the Center for the National Interest, said, "It seems highly likely the rhetoric and policy actions from Washington and Seoul will get tougher come May when a new government takes over South Korea."
Yoon will be inaugurated as president in Seoul on May 10.
Deputy Secretary of State Wendy Sherman said during a House Foreign Affairs Committee hearing Wednesday that Yoon's delegation, which is visiting Washington this week, discussed with the Biden administration a need "to ensure that we take some strong actions" to let Pyongyang know that it cannot continue to raise tensions "without any consequences."
On Thursday, Yoon stressed "the importance of strong deterrence based on South Korea-U.S. military alliance" during a visit to U.S. Army Garrison Humphreys in Pyeongtaek, 64 kilometers south of Seoul.
Kim Yo Jong's nuclear warning was in response to South Korean Defense Minister Suh Wook's remarks on April 1, when President Moon Jae-in's top general said Seoul has the capability to launch precision strikes on North Korea.
Kim Yo Jong's initial response to Suh on Sunday criticized the defense minister for mentioning a "'preemptive strike' at a nuclear weapons state."
It is unusual for a Moon government official to issue strong remarks against North Korea because it has been careful to avoid offending Pyongyang, some experts said.
South Korea's 'exasperation'
Experts think Suh's remarks reveal frustration with North Korea's continuing to dial up tension despite Moon's diplomatic overtures and peace efforts since taking office in May 2017.
"The South Korean government has been under increasing pressure in recent weeks as it becomes evident even to [it] … that North Korea is on this path and that there's nothing South Korea's engagement policy that it tried has changed North Korea's approach in any respect," Revere said.
Robert Manning, a senior fellow at the Atlantic Council, said Suh's remarks reflect "a sense of exasperation that the response to President Moon's persistent calls for dialogue is only insults and missile tests."
Moon brokered the first summit between Washington and Pyongyang, held in Singapore in June 2018. But nuclear talks broke down at a summit in Hanoi in February 2019, and North Korea has since returned to testing missiles and rockets.
Working-level talks in Stockholm, Sweden, between Washington and Pyongyang in October 2019 also broke down. To resume the dialogue, Moon tried to push for a peace declaration to end the Korean War after making a speech at the U.N. in September 2021. In February, with only three months left in his term, he said Washington and Seoul agreed on the wording of the declaration. All the while, North Korea has been conducting rounds of tests.
"Pyongyang is more interested in strengthening its missile and nuclear capabilities than in nuclear negotiations," Manning said.
He went on: "The continued spurning of President Moon's efforts to restart dialogue and rejection of the Biden administration's call for unconditional talks suggest Kim will not trade his nuclear weapons and trust the U.S. to provide assurance."
The U.S. has been offering to engage in talks with North Korea without preconditions since completing its policy review on North Korea in April 2021. But, Manning added, the Ukraine war has made North Korea more skeptical of U.S. security assurances that would come with a denuclearization agreement.
Ukraine received security assurances from the U.S. and Russia when it gave up its nuclear arsenal, as laid out in the 1994 Budapest Memorandum. But Russia ended up invading its neighbor on February 24, and the U.S. has declined to put troops on the ground in Ukraine.
Ken Gause, director of the Adversary Analytics Program at CNA, said although North Korea's verbal nuclear warning was in response to Suh's remarks, the warning is also directed against the incoming government.
"That's strategic messaging to the incoming Yoon administration, which [Pyongyang] expects to be very aggressive in support of deterrence and alliance building," Gause said. While campaigning before the March 9 vote, Yoon said a preemptive strike was an option against an impending threat if there was no other option.
On Tuesday, Yoon's spokesperson Kim Eun-hye said, "Preemptive strikes are one of the actions accepted in the world, including at the U.N., as being usable not in a preventive sense but when a preemptive threat persists." She added, "We will respond without the slightest error to North Korea's provocations and security threats."
On Wednesday, Yoon's delegation in Washington discussed with White House national security adviser Jake Sullivan a potential deployment of U.S. strategic assets such as nuclear bombers and nuclear-powered submarines to South Korea.
"Deploying the strategic assets is an important element of reinforcing the extended deterrence, and the issue naturally came up during the discussion," Park Jin, the head of the delegation, said to reporters after the meeting.
Journalists Sanghoon Lee and Joeun Lee of VOA's Korean Service contributed to this report.