U.S. Secretary of Defense Pete Hegseth, speaking at the Association of Southeast Asian Nations Defense Ministers’ Meeting in Kuala Lumpur, used blunt language on Saturday to single out Beijing for an increase in "destabilising actions" in the South China Sea and pledged American support to bolster regional responses. Hegseth said the United States was prepared to share tools and technology with Southeast Asian countries to help them respond collectively to what he described as "aggressive" Chinese behaviour.

The remarks mark a visible step in Washington’s effort to translate strategic reassurance into concrete capabilities for partners that face persistent maritime pressure. The South China Sea is a vital artery for global trade and a longstanding flashpoint of overlapping territorial claims, with the maritime competition involving resource access, commercial navigation and national sovereignty. For capitals in the region, the question is how to strengthen deterrence without precipitating escalation between the world’s two largest military powers.

Hegseth’s pledge comes amid a broader U.S. strategy to deepen interoperability and capacity building with allies and partners across the Indo-Pacific. While the secretary did not list specific systems or transfer packages, technology assistance typically involves surveillance and maritime domain awareness enhancements, intelligence-sharing arrangements, and non-lethal equipment that can improve situational awareness and joint responses. For smaller claimants in the region, access to such capabilities can tilt the balance in maritime encounters and provide public reassurance to domestic constituencies concerned about sovereignty and economic stability.

The announcement also places pressure on ASEAN’s diplomatic architecture. The grouping prizes consensus and non-alignment, and its members are split between those that have direct maritime disputes with China—such as the Philippines, Vietnam and Malaysia—and those that prioritize close economic ties with Beijing. A U.S. push to arm or equip states, even with ostensibly defensive tools, could deepen divisions within ASEAN about how to manage great-power competition and preserve regional autonomy.

International law factors prominently in the background. The 2016 arbitration ruling under the United Nations Convention on the Law of the Sea remains a cornerstone for many claimant states seeking legal recourse against expansive maritime claims. Washington’s technology pledge can be read as an attempt to uphold principles of freedom of navigation and the peaceful resolution of disputes, while avoiding direct military confrontation that would risk a broader crisis.

China is likely to view intensified U.S. technology transfers as further militarisation of a diplomatic contest, increasing the chance of reciprocal measures or diplomatic protest. For the United States and its partners, the immediate challenge will be calibrating assistance to strengthen deterrence and collective response without closing diplomatic channels or hardening military postures in ways that make incidents more likely.

Hegseth’s statements in Kuala Lumpur signal Washington’s readiness to move beyond rhetorical support to practical capacity-building, a shift with real implications for regional security dynamics. How Southeast Asian states balance that support with their economic and political ties to Beijing will shape the trajectory of Indo-Pacific stability in the months ahead.