U.S., South Korean, and Japanese officials warned on Wednesday that they would take “unparalleled” measures against North Korea if it conducted a nuclear test, a step that Pyongyang is widely expected to take in the coming weeks.

Speaking alongside U.S. deputy secretary of state Wendy Sherman and Japanese Vice foreign minister Takeo Mori in Tokyo, South Korean first vice foreign minister Cho Hyon-dong emphasized that an “unparalleled scale of response would be necessary if North Korea pushes ahead with a seventh nuclear test,” according to Reuters. Sherman added that such a test would be “reckless and deeply destabilizing for the region” and would have far-reaching implications outside of the Korean peninsula.

“We hope indeed that everyone on the [United Nations] Security Council would understand that any use of a nuclear weapon will change the world in incredible ways,” Sherman said—an apparent warning to Russian leader Vladimir Putin, who threatened to use nuclear weapons to defend the Russian-occupied territories in Ukraine in a televised speech in late September.

Tensions have risen on the Korean peninsula since early 2022. North Korea has conducted dozens of missile tests, including the launch of a ballistic missile over Japanese territory earlier this month. In September, South Korea and the United States conducted joint military exercises involving the USS Ronald Reagan aircraft carrier, which North Korea swiftly condemned and used to justify further missile launches.

Also in September, North Korea passed a law forbidding the surrender of its nuclear weapons—effectively ending the sporadic three-decade nonproliferation negotiations between Washington and Pyongyang—and declared that it would pursue the first use of nuclear weapons in any future war.

While South Korea does not possess nuclear weapons, the United States has vowed to defend Seoul from a North Korean invasion. During a separate press conference with Cho on Tuesday, Sherman vowed that the United States would make “full use” of its military capabilities, including both conventional and nuclear weapons, in order to defend Japan and South Korea against a potential attack.

The trilateral meeting on Wednesday marks the first joint summit of the three countries since the inauguration of South Korean president Yoon Suk-yeol in May. Widely regarded as a hardliner on North Korea in contrast to his liberal predecessor Moon Jae-in, Yoon has pledged to strengthen Seoul’s alliance with the United States. He has also sought to improve ties with Japan, which have remained strained since Korea’s independence, owing to controversies over the country’s time as a Japanese colony from 1910 to 1945.

Trevor Filseth is a current and foreign affairs writer for the National Interest.

Image: Reuters