The United States and Japan on 9-10 June 2025 jointly reaffirmed their commitment to the complete denuclearisation of North Korea and explicitly rejected Russia's characterisation of Pyongyang's nuclear ambitions as a 'closed issue', according to a joint statement issued following bilateral defence talks in Tokyo. The allies convened the Extended Deterrence Dialogue at Japan's foreign ministry on Monday and Tuesday, underscoring deepening security cooperation amid mounting regional threats.

What the Joint Statement Said

The statement declared that 'both delegations discussed China's dramatic and opaque nuclear weapons buildup and rejected Russia's notion that the DPRK's pursuit of nuclear weapons was a closed issue.' DPRK refers to the Democratic People's Republic of Korea, North Korea's official name.

The two sides also discussed US efforts to modernise and adapt its nuclear forces, alongside Japan's evolving defence policy and capabilities, citing 'increasing regional nuclear threats' as the driving rationale.

Tokyo's Push for Multilateral Stability

Japan used the dialogue to encourage the US to pursue multilateral 'strategic stability' talks aimed at averting a nuclear arms race, reducing nuclear risks, addressing concerns about nuclear testing, and bolstering transparency — including through arms control dialogues with China and Russia. This reflects Tokyo's increasingly assertive posture on non-proliferation, a notable shift from its traditionally cautious diplomatic stance.

The meeting was co-chaired by the US State Department, the US Department of Defence, and Japan's foreign and defence ministries. Participants included representatives from the Japan Joint Staff, US Joint Staff, US Strategic Command, US Indo-Pacific Command, and US Forces Japan.

US Reiterates Concern at IAEA Board Meeting

In a parallel development on Tuesday, Howard Solomon, chargé d'affaires ad interim at the US Mission to International Organisations in Vienna, echoed Washington's position before the International Atomic Energy Agency (IAEA) board of governors meeting.

'Statements and actions by some to state that these programs are a closed issue are unacceptable and undermine the nonproliferation regime,' Solomon said, according to a transcript from the US mission's website. He added that the US remains 'gravely concerned' about North Korea's ongoing nuclear activities.

'The DPRK continues to advance its destabilising weapons of mass destruction and ballistic missile programs in violation of multiple UN Security Council resolutions. These programs pose a threat to America, our allies, and others, and undermine security in the region,' he said.

Pyongyang's Escalating Nuclear Activity

Solomon also highlighted that Pyongyang last week unveiled purportedly new centrifuges for producing weapons-grade nuclear material and announced plans to expand its nuclear forces 'at an exponential rate.' This comes amid a broader pattern of North Korea accelerating weapons development in defiance of international sanctions, with 2024 and early 2025 marking a particularly active period of missile tests and nuclear facility expansions.

Notably, Russia's deepening ties with Pyongyang — including reported arms transfers linked to the war in Ukraine — have complicated the traditional non-proliferation consensus, making Washington and Tokyo's joint pushback diplomatically significant. How the alliance manages the triangular dynamic between China, Russia, and North Korea will define the next phase of Indo-Pacific security architecture.