The U.S. secretary of defense said Saturday that Beijing's aggression in the South China Sea has "increased", and pledged to continue dialogue to "ensure China is not seeking to dominate" ASEAN nations.

Speaking at a meeting of ASEAN leaders in Malaysia, Pete Hegseth labelled Chinese actions in the disputed waterway "provocative" and said they show a lack of respect for their neighbours.

"China's sweeping territorial and maritime claims in the South China Sea fly in the face of their commitments to resolve disputes peaceful... Here, the opportunity to talk is something we value... But inside that dialogue, we are most importantly watching actions," Hegseth said.

Earlier this week Hegseth met with his Chinese counterpart Dong Jun on the sidelines of the summit in Kuala Lumpur.

He said he directly raised U.S. concerns over Chinese activities in the South China Sea, around Taiwan and toward U.S. allies and partners in the region.

China's defense ministry issued a cautious response, emphasizing its longstanding positions.

Their meeting follows a Sept. 9 video call between Hegseth and Dong and reflects ongoing efforts to manage tensions in the Indo-Pacific even as strategic differences, particularly over Taiwan and freedom of navigation, remain pronounced.