WASHINGTON: President Joe Biden and his South Korean counterpart Yoon Suk Yeol warned North Korea on Wednesday it would face a nuclear response and the “end” of the leadership there if Pyongyang uses its own arsenal.

Speaking at the White House after Oval Office talks during only the second state visit so far in the Biden presidency, the two leaders said the US security shield for South Korea was being strengthened in the face of the nuclear-armed North’s aggressive missile tests.

And they made clear that if North Korea attacks the South or the United States, the response will be devastating.

“A nuclear attack by North Korea against the United States or its allies… will result in the end of whatever regime were to take such an action,” Biden told reporters at a joint press conference with Yoon.

‘Washington declaration’ aims to upgrade US military support for S. Korea, including deployment of a nuclear submarine

Yoon said his priority was to secure peace through “superiority of overwhelming forces and not a false peace based on the goodwill of the other side”.

“In the event of a North Korean nuclear attack,” he said, Washington and Seoul have agreed to “respond swiftly, overwhelmingly and decisively using the full force of the alliance, including US nuclear weapons.”

A military honour guard and hundreds of guests massed outside the White House where Yoon and his wife, Kim Keon Hee, arrived for a day of pomp and ceremony.

Yoon and Biden issued what was titled the “Washington declaration”, bolstering the US nuclear umbrella over South Korea, which is increasingly nervous about the sabre-rattling in the north.

“President Biden has reaffirmed his ironclad commitment to extended deterrence towards the Republic of Korea,” Yoon said.

This will include a mechanism for the two countries to share information and consult in event of a North Korean attack, even if US commanders will still retain full control on the nuclear weapons. It will also see more integration of South Korea’s conventional military with US nuclear forces.

A senior US official described the new arrangement as an echo of moves last seen when Washington oversaw the defence of Europe against the Soviet Union.

“The United States has not taken these steps, really, since the height of the Cold War with our very closest handful of allies in Europe. And we are seeking to ensure that by undertaking these new procedures, these new steps, that our commitment to extended deterrence is unquestionable,” the official said.

US officials stressed that there are no plans to station nuclear weapons in South Korea — a difference from the Cold War, when US strategic weapons were deployed to Europe.

In addition, Seoul reiterated its pledge in the declaration not to seek its own nuclear arsenal.