In a major move to upgrade their defense integration, the United States and Japan have agreed to set up a facility in Japan for the joint production of advanced medium-range air-to-air missiles.

The deal was announced by Japanese Defense Minister Shinjiro Koizumi on Wednesday in the central Philippine province of Cebu, where he met with US Defense Secretary Pete Hegseth, on the sidelines of the annual Association of Southeast Asian Nations Defense Ministers' Meeting Plus.

The move comes at a time when Japan is pushing ahead with full-scale re-militarization, increasingly challenging the postwar international order. The agreement not only accelerates Japan's military buildup, but also fuels the reemergence of neo-militarism in the country as the collaboration further weakens the constraints of Japan's pacifist Constitution.

The deepening military cooperation between the two countries is likely to escalate regional tensions. The missiles to be produced are part of "Operation Supercharge", a joint initiative that is essential for Japan's US-made F-35 fighter jets. By establishing the final assembly line for the advanced air-to-air missiles in Japan, the two sides have progressed beyond equipment procurement and joint drills to deep military collaboration, characterized by localized production and integrated military industry chains.

The arrangement will substantially enhance Japan's capacity for air operations and rapid deployment across the region. This is not merely a military technology partnership but also a strategic move by the US to strengthen its military positioning in Asia and establish exclusive security blocs, threatening regional peace and stability.

The expanding US-Japan military cooperation is also shepherding the Philippines into its fold, as highlighted by the deployment of Japanese troops to the Philippines to take part in Balikatan 2026. Conducted from April 20 to May 8, it was the largest US-Philippines joint exercise to date. Additionally, Japan has agreed to supply the Philippines with decommissioned destroyers equipped with anti-ship missiles. The objective is to "enhance" the Philippines' naval capabilities and counter what the two countries claim is China's "assertiveness" in the South China Sea.

Meanwhile, the US continues to strengthen its alliance with the Philippines to enhance interoperability between their forces as part of a strategy to contain China by expanding its military posture along the so-called first island chain.

The military buildup in Southeast Asia runs counter to ASEAN's security philosophy, which emphasizes maintaining a stable and peaceful regional environment through cooperation, dialogue and respect for sovereignty. Such actions risk provoking regional bloc confrontation and disrupting the region's long-standing stable security landscape.

In recent years, Southeast Asia has generally maintained a positive momentum of peaceful development despite the complex and rapidly changing international geopolitical situation. Regional economic and trade cooperation has continued to deepen, as evidenced by the growth in intra-regional trade, expanding investment flows, and the effective implementation of frameworks such as the Regional Comprehensive Economic Partnership.

The US and Japan's expansion of weapons production in Asia and their bloc-based military cooperation and coordination heighten the risk of a regional arms race and harm the common interests of all countries in the region. The development of bilateral relations and security cooperation between the US and Japan should not undermine regional peace and stability, nor should it target other countries or harm their interests, as Chinese Foreign Ministry spokesman Guo Jiakun said on Thursday.

All parties should remain committed to cooperation and uphold ASEAN's independent security architecture. It is in the best interests of regional countries to replace confrontation with cooperation and resolve differences through dialogue, thereby sustaining the momentum of peace, stability, and prosperity and safeguarding their hard-won development gains. Southeast Asia does not need military cliques or new confrontational blocs.