The defense ministers of Japan and the Republic of Korea (ROK) agreed to maintain close cooperation with the United States to deter North Korea’s nuclear threat and Pyongyang’s growing military ties with Russia, the ROK Defense Ministry announced.
During their September 2025 meeting in Seoul, Japanese Defense Minister Gen Nakatani and ROK Defense Minister Ahn Gyu-back also reaffirmed their commitment to denuclearization of the Korean Peninsula and pledged to pursue cooperation in advanced defense technologies.
The defense chiefs highlighted the importance of the annual trilateral Exercise Freedom Edge, hosted by U.S. Indo-Pacific Command (USINDOPACOM). The September 2025 iteration, held against a backdrop of North Korea’s ongoing missile threats, featured upgraded aerial, naval and cyber capabilities, according to the ROK Defense Ministry. The drills, which took place off South Korea’s Jeju Island, featured U.S. Air Force and Marine Corps assets in the “most advanced demonstration of trilateral air and naval cooperation to date,” USINDOPACOM stated. South Korea is formally known as the ROK.
The defense chiefs’ meeting marked the first official trip to Seoul by a Japanese defense minister since 2015. The talks came after ROK President Lee Jae-myung met with Japanese Prime Minister Shigeru Ishiba in August 2025 in Tokyo, where they agreed to deepen security and economic ties.
In Munich, Germany, in February 2025, Japanese Foreign Minister Takeshi Iwaya, then-ROK Foreign Minister Cho Tae-yul and U.S. Secretary of State Marco Rubio reaffirmed the trilateral partnership. They pledged robust security cooperation, regular combined exercises and strengthened deterrence through the U.S.’s longtime alliances with Seoul and Tokyo. Their statement underscored the nations’ opposition to any unilateral efforts to change the status quo by force in the Indo-Pacific.
The allies’ trilateral cooperation comes as North Korea deepens military collaboration with Russia. In June 2024, Moscow and Pyongyang signed a defense pact pledging mutual aid. Analysts and officials say North Korea has sent weapons and troops to aid Russia’s war against Ukraine in exchange for military and economic assistance. Such transfers violate United Nations Security Council resolutions targeting Pyongyang’s illicit weapons of mass destruction program.
China’s September 2025 military parade in Beijing, attended by North Korean dictator Kim Jong Un, and increased China Coast Guard patrols near disputed islands in the East China Sea have further heightened tensions.
Sentry is a professional military magazine published by U.S. Strategic Command to provide a forum for national security personnel.
