Delegates at a regional naval forum - including representatives of China, the United States, and Japan - have agreed on a set of rules meant to prevent accidents and miscommunication at sea.
The agreement was adopted by all 21 member nations during a meeting of the Western Pacific Naval Symposium, which opened Tuesday in the eastern Chinese port city of Qingdao.
Chinese Navy Commander Wu Shengli said he hopes the meeting will help reduce tensions among Asia-Pacific countries.
"We hope that we can increase understanding and trust among navy forces across the region and further promote pragmatic maritime cooperation and achieve expected goals through discussions at this year's symposium," said Wu.
Despite the focus on cooperation, the two-day symposium has been complicated by military friction between Beijing and its neighbors.
China refused to invite Japan to a multinational naval drill held during the forum. Japan's delegate also said there are no plans to meet one-on-one with his Chinese counterparts at the symposium.
Japan-China ties have been strained by a worsening dispute over territory in the East China Sea. Beijing is also upset over what it sees as Tokyo's reluctance to atone for abuses before and during World War II.
Many of China's other neighbors, especially those bordering the South China Sea, accuse Beijing of using bullying tactics to defend its vast, disputed maritime claims.
Small-scale clashes occasionally break out between surveillance or fishing vessels from various countries. Some fear the incidents could someday spark a wider military clash.
However, naval officers from China and the United States told Reuters the document was not meant to directly address problems, including territorial issues, pitting China against several of its neighbors in the East and South China Seas.
The United States wants clearer operational communications with the growing Chinese fleet, arrangements in part hampered by different interpretations of what operations are acceptable in international waters, U.S. naval officers have said.
The risks of a mishap were highlighted in December when the U.S. guided missile cruiser USS Cowpens had to take evasive action in the South China Sea to avoid hitting a warship supporting China's first aircraft carrier, the Liaoning.
A late draft of the non-binding document, obtained by Reuters, is essentially a handbook for maneuvers and communication when naval ships and aircraft from the signing countries encounter each other unexpectedly.
Navies are told to fire off flares in green, yellow and red in different situations and given a list of English-language terms.
“The document is not legally binding, rather, it's a coordinated means of communication to maximize safety at sea,” the draft reads.
The final version has not been publicly released, but a naval official privy to the discussions said the language in the draft was close to what had been formally agreed upon.
The document defines “unplanned encounters” as when vessels from two countries meet “casually or unexpectedly.”
Assertive China stokes concerns
Beijing's increasingly assertive stance on maritime security in what it sees as its territorial waters has stoked concerns in the region, particularly as its military and civilian ships increase patrols in disputed areas.
Chinese and Japanese ships routinely shadow each other near a chain of disputed islets in the East China Sea, a development which analysts have said raises the risk of a conflict.
“The number of communications between the Japanese and Chinese defense forces is small,” said Japanese Navy Captain Masahiro Sakurai without elaborating.
The United States has long-standing defense treaties with Japan and the Philippines, raising the prospect of Washington being drawn into a potential conflict if a collision sparks wider tensions.
It is unclear whether this agreement clears up differences rooted in different interpretations of military activity.
Beijing has objected, for example, to U.S. surveillance operations near its coast, even if Washington insists they are in international waters.
Separately, China and the 10 countries of the Association of South East Asian Nations (ASEAN) are negotiating a binding Code of Conduct to ease tensions in the South China Sea before territorial disputes can be resolved.
The code extends far beyond improved communications, seeking to halt military exercises in disputed waters and limit construction on empty reefs and islands, diplomats say.
Some information in this report was contributed by Reuters.