Days of heated diplomacy at Southeast Asian talks have ended in failure, as deep splits over China prevented the ASEAN grouping from issuing its customary joint statement for the first time.
The Philippines lambasted the failure at the end of the talks on Friday, saying "it deplores the non-issuance of a joint communique... which was unprecedented in ASEAN's 45-year existence".
Foreign ministers from the 10-member bloc have been wrangling since Monday to hammer out a diplomatic communique, which has held up progress on a separate code of conduct aimed at soothing tension in the flashpoint South China Sea.
China claims sovereignty over nearly all of the resource-rich sea, which is home to vital shipping lanes, but ASEAN members the Philippines, Vietnam, Malaysia and Brunei have competing claims in the area.
The long-stalled code of conduct, strongly supported by the United States, is seen as a way of reducing the chances of a spat over fishing, shipping rights or oil and gas exploration tipping into an armed conflict.
The Philippines had insisted ASEAN refer to an armed stand-off with China last month over a rocky outcrop known as the Scarborough Shoal, but Cambodia - a Beijing ally and chair of the meeting - resisted.
Taking "strong exception" to Cambodia, the Philippine statement said divisions undercut ASEAN's goal of tackling disputes as a bloc "and not in a bilateral fashion - the approach which its northern neighbour (China) has been insisting on".
The Philippines and the United States called this week for a unified ASEAN that could use its collective clout to negotiate with China, while Beijing prefers to deal with its smaller neighbours individually.
'Tense back and forths'
Diplomatic sources, speaking anonymously to AFP, referred to angry exchanges during behind-the-scenes talks, with an emergency meeting called for early Friday morning also failing to break the deadlock.
"I think it would be fair to say that tempers in some of the private meetings have run hot. There have been some very tense back and forths," one US official said.
China is a key bankroller of the much-criticised host Cambodia and some diplomats said Beijing had twisted arms in Phnom Penh to prevent any reference to the South China Sea disputes in the communique.
Cambodian Foreign Minister Hor Namhong expressed regret at the discord within ASEAN, but said he could "not accept that the joint communique has become the hostage of the bilateral issue (between the Philippines and China)".
Indonesian Foreign Minister Marty Natalegawa, who played a key role trying to broker a compromise, expressed "deep, profound disappointment" at the lack of consensus within the bloc.
"There is still a common view that we must, if anything, reinforce our efforts to work on the COC (code of conduct), to begin our talks with the Chinese on the COC," he added.
Foreign ministers said Sunday they had agreed "key elements" of a draft code to be presented to China, but these were not released to the media.
China was also cool on the idea of starting negotiations, almost 10 years since the idea of creating a code was first agreed, saying it would only negotiate "when conditions are ripe".
Analysts said the friction could "contaminate" future negotiations between ASEAN and China.
"Cambodia is showing itself as China's stalking horse. This will make negotiating a final code of conduct with China more difficult," said Southeast Asia expert Carl Thayer.
"I find it difficult to believe that ASEAN foreign ministers cannot come up with some formulation that satisfies all parties."
The failure to issue a joint statement marks a sharp deterioration in efforts to cool tensions following recent incidents of naval brinkmanship over the oil-rich waters.
China, whose trade and investment ties with Cambodia have surged in recent years, has warned that "external forces" should not get involved in the dispute. Vietnam, Malaysia, Brunei and Taiwan also lay claim to parts of the South China Sea.
The United States has stressed it is neutral in the long-running maritime dispute, despite offering to help boost the Philippines' decrepit military forces.
US Secretary of State Hillary Clinton played down the deadlock within ASEAN at a news conference in Phnom Penh on Thursday evening.
"I have worked in many multilateral settings, and it is not at all unusual for much more mature organisations to be working on and discussing and even arguing about certain matters past the deadlines in order to try to see if there's a way forward," she said.