One of the United States' most senior navy commanders has said he would like Australia to carry out naval patrols close to territory claimed by Beijing in the South China Sea - a move that would provoke significant anger within the Chinese government.
Vice Admiral Joseph Aucoin, Commander of the massive, Japan-based 7th Fleet, stressed the call was Australia's, but went further than any senior US defence figure has gone previously in bluntly saying it would be valuable for other countries including Australia to challenge Beijing's assertiveness rather than leave it to the US. 
Admiral Aucoin's remarks in Sydney come just a week after it emerged that China has placed missiles on islands in the contested waters of the South China Sea. They also come ahead of the anticipated release of the Turnbull government's Defence white paper, which will focus heavily on building Australia's maritime power in response to the growing uncertainty in Asia provoked by China's rise.
Admiral Aucoin said he wished the challenge to Beijing's island-building and unilateral territorial claims in the strategically vital waters were not "portrayed as the US versus China" but rather that "all countries, no matter what the size or strength can pursue their interests based on the law of the sea".
Asked whether that meant all countries with an interest in passage through those waters should be doing similar operations to the US's two recent "freedom of navigation" patrols close to Chinese-claimed territory, he said: "Personally, it's up to those countries but I think it's in our best interests to make sure those sea lines remain open and I'll leave it at that."
Asked then whether that could be interpreted as saying it would be valuable for Australia to do freedom of navigation operations within 12 nautical miles of China's claimed territory, he replied: "Yes."
Sailing within 12 nautical miles constitutes a challenge to territorial claims as this is the distance sovereignty extends from land into the sea.
Admiral Aucoin's comments go considerably further than any US figure has done before. Admiral Aucoin, who is visiting several cities including Canberra, said he was discussing the South China Sea with Australian counterparts but had "not specifically" discussed patrols within 12 nautical miles.
As commander of the 7th Fleet - the US's largest - Admiral Aucoin is in charge of the two US ships that have so far carried out such patrols.
Admiral Aucoin also vowed that the presence of Chinese missiles on islands would not deter the US from continuing freedom of navigation operations.
He said he was surprised and concerned by the "scale and speed" of China's island-building, which he condemned as "destabilising".
"The scale and the speed of the reclamation of China has been alarming ??? I don't know what their intentions are, but ??? we're going to sail, fly, operate in these waters and be prepared for any contingency."
About two thirds of Australia's trade passes through the South China Sea. But the waters are the subject of territorial disputes between China and neighbours including Vietnam, the Philippines and Taiwan. Tensions have been exacerbated by China's rapid building of artificial islands complete with military-grade runways and ports. That took another major step last week with the revelation that Beijing had placed surface-to-air missiles on the Paracel Island chain.
Australia has long been pondering carrying out its own naval patrols within 12 nautical miles of territory which Beijing claims - or in some cases has built - but which are not recognised by Canberra or its allies.
The purpose of these patrols would be to signal to China that its cannot use these unproven territorial claims to impose control over the waters of the South China Sea. But it has not yet decided to go ahead.
Labor's defence spokesman Stephen Conroy said the Turnbull government was hiding its lack of action behind "vague" language.
"Instead of waffle, the Turnbull government should be clear about whether it supports Australia conducting a freedom of navigation operation as a demonstration of our support for the international system in the South China Sea," he said.
Defence Minister Marise Payne said Australia had for years exercised freedom of navigation and flight and would continue to do so - though she was referring to military movements that do not go within 12 nautical miles of the sensitive territory claimed by China.
"As Vice-Admiral Joseph Aucoin said, freedom of navigation exercises are a matter for each individual country," she said.
In an apparent reference to more robust patrols within the 12-mile limit, she said: "The Government will not comment publicly on the specific details of future [Australian Defence Force] activities."
The Defence white paper, which could be released as soon as this week, will focus heavily on naval power, committing the government to buying 12 new submarines and a fleet of new surface ships. The attention the Navy reflects defence planners' view that tensions in the Indo-Pacific region will continue as power shifts towards Asia, particularly China, and countries build their defence force accordingly.
Beijing has repeatedly vowed it would not militarise its artificial islands - a promise that appears to have been undermined by the presence of missiles. Admiral Aucoin declined to say whether he believed Beijing was already militarising the islands.
Asked whether he was concerned that China would soon start flying fighter planes and other military aircraft from the islands, he said: "I think we need to be prepared for scenarios and whether we fly or sail through those waters, be ready for a range of missions."
"Trillions of dollars of commerce go through there ... so we should ensure [the sea lanes] remain open, that we will continue sailing in those waters.
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