Southeast Asian countries on Sunday expressed concern over "increased tensions" in the South China Sea and called for stepped-up talks with China, in what the United States said was a setback for Beijing's efforts to play down the disputes.
But there was no specific mention of China in the final statement from an Association of Southeast Asian Nations (ASEAN) meeting and the 10 nations did not take up a U.S. and Philippine call for a freeze on provocative acts in the sea.
A senior U.S. official said ASEAN countries' concern over China's maritime actions was at an "all-time high" based on private conversations, although their public statements were more guarded to avoid antagonizing China.
"We urged all parties concerned to exercise self-restraint and avoid actions which would complicate the situation and undermine peace, stability, and security in the South China Sea," ASEAN said in a communique following their meeting this weekend in the Myanmar capital Naypyitaw.
The United States is using the meeting of the region's foreign ministers in Myanmar to step up its engagement in the off-shore tension, by calling for a moratorium on actions such as China's planting in May of an oil rig in waters that Vietnam also claims.
The ASEAN Regional Forum brings together 27 countries including the United States, China, Russia, Japan, India and Australia.
U.S. ally the Philippines has also called for a freeze as part of a three-step plan to ease tension in the resource-rich sea, through which passes $5 trillion of trade a year.
The communique only "noted" that proposal and the language it used was little changed from its previous statement on the South China Sea issue in May.
However, it did call for ASEAN and China to finalize a proposed Code of Conduct to ease maritime tensions, including "concrete elements" to promote trust and confidence.
"Significant setback" for China
Senior U.S. officials accompanying Secretary of State John Kerry at the weekend talks described the communique's wording as a new and strong criticism of recent Chinese actions.
"This language represents a significant setback for China's efforts to play for time and change the subject," said one senior U.S. administration official.
ASEAN and China signed a trust-building agreement in 2002, committing to exercise "self-restraint" in activities that would escalate disputes, such as occupying islands and reefs or building on them. Most claimants have flouted those guidelines, leading to rising tension in the South China Sea between four ASEAN claimant nations and China, which claims 90 percent of the waters.
The Philippines accused China in May of reclaiming land on the disputed Johnson South Reef and said it appeared to be building an airstrip. Taiwan is building a $100 million port next to an airstrip on the lone island it occupies in the disputed region.
As well as Johnson South Reef, a senior Philippine navy official told Reuters that China was continuing land reclamation work on Gaven, Cuarteron and Eldad Reefs in the disputed Spratlys chain.
A senior State Department official said ASEAN members had made clear they were "increasingly concerned about the escalatory pattern of behavior".
"It is reasonable to conclude that indicates the Chinese are indeed feeling the heat. The movement is away from diversionary topics, the happy talk issues between China and ASEAN, in the direction of significant engagement on the South China Sea itself," the official said.
ASEAN and China have begun talks on the Code of Conduct but made little substantive progress so far.
The rancor has split ASEAN, with several states including some of the claimants reluctant to antagonize Asia's economic giant.
China rejects U.S. involvement in the dispute and has already dismissed the proposal for a freeze. China accuses the United States of emboldening claimants such as the Philippines and Vietnam with its military "pivot" back to Asia.