US-China ties in troubled waters
Beijing's growing assertiveness over maritime interests raising tensions

Greg Torode, chief Asia correspondent in Singapore

The vast calms of the South China Sea belie a turbulence that is increasingly defining tensions between China and the US as well as the region.

China's increasing military and diplomatic assertiveness over the disputed South China Sea dominated discussions in public and in private during the informal Shangri-La Dialogue in Singapore over the weekend.

While Chinese and US officials sharpened divisions during open exchanges, behind the scenes, Southeast Asian nations discreetly raised alarms about a fresh push from Beijing to scupper a regional approach to finding solutions.

US Secretary of Defence Dr Robert Gates gave the strongest outline yet of Washington's worries, describing it as a "growing concern".

While he stayed out of the sovereignty dispute, he said "we oppose the use of force and actions that hinder freedom of navigation", adding that stability and "free and unhindered economic development" must be maintained.

"We object to any effort to intimidate US corporations or those of any nation engaged in legitimate economic activity," he said.

That pressure has only intensified in the two years since the South China Morning Post reported that Exxon Mobil had been told privately by Chinese envoys to pull out of its deals with Vietnam or face business reprisals in China. The sea's Spratly Islands are claimed in whole by China and Vietnam and in part by the Philippines, Malaysia and Brunei.

While holding oil and gas potential, its greatest value is probably strategic, with the Spratlys straddling the sea-lanes that carry the bulk of China's, Japan's and South Korea's oil. The South China Sea is also home to China's expanding submarine fleet, with a base at Sanya , Hainan , closer to deep water than any other point on the mainland and a vital access point to the Pacific and Indian oceans.

China last year formalised its long-standing historic claims to the area, insisting much of sea is part of its exclusive economic zone.

Beijing has also strengthened fishing enforcement, with former naval vessels converted into fisheries protection vessels, and has staged its most extensive air and sea exercises yet in recent months.

US naval officials confirm that US patrols in the area are increasing, despite China's warnings that it cannot accept surveillance activity - something the US and other countries insist is the kind of routine military activity allowed in international waters.

General Ma Xiaotian , deputy chief of the PLA General Staff, made clear at the weekend that surveillance by US ships and planes would not be accepted. He listed it as a condition for resuming normal military ties, along with an end of arms sales to Taiwan.

"We are not treating it as a 'Chinese lake', we do allow innocent passage," one PLA official said later. "But I'm sorry, US surveillance is not innocent passage ? the concern of China must not be underestimated."

Chinese officials have also warned US officials in recent months that the South China Sea was a "core interest" of China, putting it alongside Taiwan and Tibet in importance.

Southeast Asia is also feeling the heat. Beijing is telling its neighbours that it will not tolerate any attempts to raise the issue at meetings with the Association of South East Asian Nations. It prefers to deal with claimant countries individually - a move that apparently puts China in the strongest position.

Rival claimant Vietnam, as chairman of Asean this year, is desperately trying to force discussions later this year on the need for a legally binding Code of Conduct. China has quashed such moves so far and has already started leaning on Indonesia, next year's Asean chief, according to a range of diplomats.

"It is leaving nothing to chance ? On this issue, China is determined to rule Asean by dividing it," one veteran regional envoy said. "And so far it is proving successful. Every Southeast Asian country has to think of its own relationship first before thinking of how to act together."

Vietnam's long-standing ally and neighbour, Cambodia, for example, has stopped supporting Hanoi's efforts in private Asean meetings on the South China Sea. Given the 10-nation grouping's consensus traditions, objectors can easily scupper discussions.

Hanoi is still pushing for the issue to be raised at an inaugural formal meeting of Asean defence ministers with their regional peers later this year. Vietnamese Defence Minister Phung Quang Thanh told the Singapore meeting that it would continue pushing for a regional solution.

He said he also hoped that "comradeship and good neighbourliness" with China could help lower tensions.

Vietnam specially wants a 2002 Declaration of Conduct in the South China Sea to be followed to the letter.

On Saturday, Gates also expressed US hopes for the "concrete implementation" of the agreement and regional solutions based on international law - both references widely seen as a swipe at China's positions.

Japan and South Korea are also paying much closer attention to the issue. "There is no other issue that really ties together all the pressures and tensions now faced by the region as China asserts itself," one Japanese official said. "There is a definite worry that things could get worse."