China has been embroiled in a row with the Philippines and Vietnam in recent months over what each government sees as intrusions and illegitimate claims in the stretch of ocean spanning key shipping lanes.
"The worry, among others that I have, is that the ongoing incidents could spark a miscalculation, and an outbreak that no one anticipated," Admiral Mike Mullen, chairman of the Joint Chiefs of Staff, said at the start of a four-day visit to China.
"We have an enduring presence here, we have an enduring responsibility. We seek to strongly support the peaceful resolution of these differences," he told foreign reporters during a news conference.
Despite unease over China's growing military capabilities and assertiveness in the disputed waters, U.S.-China military relations have thawed in recent months and Mullen's trip to China is seen as a reciprocal visit for the one his Chinese counterpart made to Washington in May.
That visit by People's Liberation Army (PLA) Chief of the General Staff Chen Bingde marked the country's highest-level military-military talks since China severed ties in early 2010, furious about $6.4 billion in U.S. arms sale to Taiwan, which Beijing considers a renegade province.
The United States has pledged its support to the Philippines in the East Sea, which is believed to harbor rich oil and gas reserves.
But Beijing insists on handling the disputes over the region on a one-on-one basis rather than multilaterally, a strategy some critics have described as "divide and conquer."
China, the Philippines, Malaysia, Brunei, Vietnam and Taiwan all claim territory in the East Sea. China's claim is the largest, forming a vast U-shape over most of the sea's 648,000 square miles (1.7 million square km), including the Truong Sa (Spratly) and Hoang Sa (Paracel) archipelagos.
China and the U.S. broached the issue at talks in Hawaii in June, and the topic could dominate the agenda at an upcoming Association of Southeast Asian Nations (ASEAN) Foreign Ministers meeting in Indonesia.
The official English-language China Daily newspaper said in an editorial July 8 that ASEAN should not tolerate attempts by outside forces to interfere in bilateral disputes, a thinly veiled swipe at the United States.
"Asia's history proves outside forces have never worked whole-heartedly for Asian peace and development," it said.
But Mullen, while emphasizing the United States' desire to see a peaceful resolution to territorial claims in the East Sea, also said Washington would not quit the region.
"The U.S. is not going away. Our enduring presence in this region has been important to our allies for decades and will continue to be so," he said.
Chinese and U.S. ships have been involved in stand-offs in the seas off China's coast in the past few years, and Beijing has repeatedly complained about U.S. reconnaissance patrols.
China is also expected to launch its first aircraft carrier soon, which would add to its growing military clout just as other powers in Asia are becoming uneasy about its increasingly strident claims over disputed seas in the region.
Asked about the carrier, Mullen suggested that having the vessel and deploying it effectively are two different things.
"There is great symbolism associated with that and I understand that. Sometimes matching the actual capability versus the symbolism, there can be a gap there," he said.