China risks violating international law if it continues to strike a defiant tone and ignores an arbitration court ruling that denies its claims in the South China Sea despite calls from the US and the head of the UN for the peaceful resolution of disputes in the oil-rich waters.
In a case that was seen as a test of China's rising power and its economic and strategic rivalry with the US, the Permanent Court of Arbitration in The Hague ruled on Tuesday that China had breached the Philippines' sovereign rights by endangering Philippine ships and fishing and oil projects.
China's ambassador to the US, Cui Tiankai, said at an international forum in Washington on Tuesday that the arbitration case "will probably open the door of abusing arbitration procedures".
"It will certainly undermine and weaken the motivation of states to engage in negotiations and consultations for solving their disputes," Mr Cui said. "It will certainly intensify conflict and even confrontation."
Mr Cui also said, however that Beijing remains committed to negotiations with other parties in the South China Sea issue.
The US, which China has accused of fuelling tensions and militarising the region with patrols and exercises, said the ruling should be treated as final and binding.
"We certainly would urge all parties not to use this as an opportunity to engage in escalatory or provocative action," White House spokesman Josh Earnest told reporters in a briefing.
The ruling is significant as it is the first time that a legal challenge has been brought in the dispute, which covers some of the world's most promising oil and gas fields and fishing areas.
US State Department spokesman John Kirby said Washington has seen signs in recent weeks of continued militarisation by China in the South China Sea.
President Barack Obama's top Asia policy adviser, Daniel Kritenbrink, said the US had no interest in stirring tensions in the South China Sea as a pretext for involvement in the region.
"We have an enduring interest in seeing territorial and maritime disputes in the Asia Pacific, including in the South China Sea, resolved peacefully, without coercion and in a manner that is consistent with international law," Mr Kritenbrink said at a forum of the Center for Strategic and International Studies.
China boycotted the arbitration hearings and described them as a farce. China's foreign ministry rejected the ruling, saying its people had more than 2000 years of history in the South China Sea, that its islands did have exclusive economic zones and that it had announced to the world its "dotted line" map in 1948.
"China's territorial sovereignty and maritime rights and interests in the South China Sea shall under no circumstances be affected by those awards," it said.
International law experts and China observers described the ruling as a legal blow to its claims in the disputed waters.
The ruling and China's defiance of it have brought China, the US, Southeast Asia and the concept of an international order based on accepted rules of behaviour to a dangerous crossroads, with one path leading to negotiations but the more likely one towards growing tensions in a politically and economically vital area, administration officials and outside experts said on Tuesday.
China claims most of the energy-rich waters through which about $US5 trillion in ship-borne trade passes every year. Brunei, Malaysia, the Philippines, Taiwan and Vietnam also have claims.
Finding for the Philippines on a number of issues, the court said there was no legal basis for China to claim historic rights to resources within its so-called nine-dash line, which covers almost 90 percent of the South China Sea.
None of China's reefs and holdings in the Spratly Islands entitled it to a 322km exclusive economic zone, it added.