US Pacific Fleet commander Admiral Samuel Locklear said the region had become the world's "most militarised" amid rapid economic growth, deepening the importance of dialogue to ensure the disputes did not lead to armed conflict.
"What's going to underlie that most importantly is a commitment to the rule of law, a commitment to international forums to solve problems and to solve disputes," Locklear told a World Economic Forum meeting in Manila.
Locklear was speaking about the various territorial disputes in the South China Sea and East China Sea that have endured for decades, but worsened in recent years amid perceived rising Chinese assertiveness.
China claims most of the South China Sea, even waters close to the shores of its neighbours and more than 1,000 kilometres from the nearest major Chinese landmass.
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Vietnam, the Philippines, Malaysia and Brunei, as well as Taiwan, claim parts of the sea, which is home to some of the world's most important shipping lanes and believed to contain huge deposits of oil and gas.
China sent a deep-water oil drilling rig into contested waters in the sea this month, sparking violent protests in Vietnam in which at least four Chinese were reported killed.
Vietnamese Prime Minister Nguyen Tan Dung said yesterday that China's decision to deploy the oil rig had "seriously threatened peace".
Locklear also defended US efforts to build up security alliances in Asia, including with countries having territorial disputes with China, following criticism by Chinese President Xi Jinping.