US Defence Secretary Pete Hegseth has urged Southeast Asian nations to stand firm and strengthen their maritime forces to counter China's increasingly "destabilising" actions in the South China Sea.

Hours later, he struck a notably softer tone online, saying that US-China ties have "never been better" and that both sides agreed to set up direct military communication channels.

Speaking at a Saturday meeting in Malaysia with his counterparts from the Association of Southeast Asian Nations, Hegseth reiterated US concerns over what he called China's aggression in the disputed waters, citing incidents such as the ramming of vessels and the use of water cannons.

He warned Beijing's provocative behaviour threatened the sovereignty of its neighbours and regional stability. "China's sweeping territorial and maritime claims in the South China Sea fly in the face of their commitments to resolve disputes peacefully," he said. "We seek peace. We do not seek conflict. But we must ensure that China is not seeking to dominate you or anybody else."  

Hegseth criticised Beijing's recent declaration of the Scarborough Shoal - seized from the Philippines in 2012 - as a "nature reserve." He told the meeting it was "yet another attempt to coerce new and expanded territorial and maritime claims at your expense."  

He urged ASEAN to hasten the conclusion of a long-delayed Code of Conduct being negotiated with China to govern behaviour in the sea... He also proposed developing shared maritime surveillance and rapid-response systems to deter provocation.

A "shared maritime domain awareness" network, he said, would ensure that any member facing "aggression and provocation is not alone." 

US Defence Secy in Vietnam to strengthen relations

Hanoi: US Defence Secretary Pete Hegseth was in Vietnam on Sunday, reaffirming a partnership built on healing the scars of the Vietnam War in a trip that will test whether Washington can reassure a vital but wary partner. Hegseth said addressing the legacies of the war, which ended 50 years ago in April, "remains the foundation of our defence relationship and a top priority for this administration and the Department of Defence." Hegseth's visit also marks 30 years of diplomatic ties between the former foes and two years since they upgraded relations to a Comprehensive Strategic Partnership, Vietnam's highest diplomatic status.  He arrived in Hanoi from Kuala Lumpur, Malaysia, where he attended a meeting of counterparts from the Association of Southeast Asian Nations.