US Secretary of State Antony Blinken speaks during a meeting with South Korean Foreign Minister Cho Tae-yul and Japanese Foreign Minister Yoko Kamikawa in New York on Monday. (Reuters)

US Secretary of State Antony Blinken said Monday that trilateral cooperation between South Korea, the US, and Japan will remain "vital" to the future of the three countries regardless of political transitions in Washington and Tokyo.

Blinken made the remarks as he, South Korean Foreign Minister Cho Tae-yul, and Japanese Foreign Minister Yoko Kamikawa met trilaterally on the sidelines of the UN General Assembly in New York, demonstrating their commitment to the three-way partnership in the face of shared challenges, including evolving North Korean threats.

"We have political transitions in Japan and the United States, but this trilateral partnership, irrespective of those transitions, will remain vital to the future of all three of our countries — a future that we are working to shape together," he said, according to a transcript released by the State Department.

He described the trilateral relationship as one of the "hallmarks" of President Joe Biden's administration, saying it is "stronger," "more effective," and "more important" than ever, given the challenges and opportunities the three countries face.

The meeting occurred as Seoul, Washington, and Tokyo have deepened their collaboration to counter threats from North Korea, which has heightened tensions on the Korean Peninsula with its recent disclosure of a uranium enrichment facility, continued weapons tests, and the launch of trash-filled balloons into South Korea.

The three sides expressed concerns over the North's uranium enrichment facility and its expanding illegal military cooperation with Russia, according to the foreign ministry in Seoul.

"They agreed to continue close coordination to lead efforts to implement UN Security Council resolutions, while responding sternly to any provocations from Pyongyang," the ministry said.

Cho emphasized that the trilateral gathering demonstrated their resolve to cooperate "closely" and respond "steadfastly" to any provocation by the North, highlighting the unwavering commitment to trilateral cooperation amid political developments.

"Since the historic Camp David summit in August last year, we have made tremendous achievements in our trilateral cooperation, and I think at all levels and in many areas," Cho said.

He referred to the first standalone trilateral summit at Camp David in Maryland in August last year, which produced a series of landmark agreements, including a "Commitment to Consult" in the event of a shared threat.

Kamikawa also underscored the importance of trilateral security cooperation amid growing regional and global security challenges.

"The security environment surrounding us is becoming increasingly severe, and the free and open international order based on the rule of law is facing serious challenges, making our strategic collaboration more important than ever," she said.

"We would like to further strengthen our coordination in dealing with North Korea and across a wide range of fields."

The cooperation among Seoul, Washington, and Tokyo gained momentum after South Korean President Yoon Suk Yeol addressed the issue of compensating Korean victims of Japan's colonial-era forced labor in March last year.

With warming ties between Seoul and Tokyo, the three countries have strengthened security cooperation through joint exercises, the sharing of ballistic missile warning data, and other efforts.

Monday's meeting marked the three diplomats' first in-person talks since their last meeting during the Group of 20 (G20) summit in Brazil in February. (Yonhap)