The U.S. Navy said it would station several new coastal combat ships in Singapore and perhaps in the Philippines in coming years, moves likely to fuel China's fears of being encircled and pressured in the South China Sea dispute.
Regional defence analysts said the ships were small, but agreed the symbolism of the moves, which come after Washington announced it was increasing its engagement in Asia, would upset Beijing.
Last month the United States and Australia announced plans to deepen the U.S. military presence in the Asia-Pacific region, with 2,500 U.S. Marines operating out of a de facto base in Darwin in northern Australia.
In coming years, the U.S. Navy will increasingly focus on the strategic maritime crossroads of the Asia-Pacific region, Chief of Naval Operations Admiral Jonathan Greenert wrote in the December issue of Proceedings, published by the U.S. Naval Institute.
He said the navy planned to station several of our newest littoral combat ships at Singapore's naval facility, in addition to the plans announced by President Barack Obama for marines to be based in Darwin from next year.
This will help the navy sustain its global forward posture with what may be a smaller number of ships and aircraft than today, he wrote.
Littoral combat ships are shallow draft vessels that operate in coastal waters and can counter coastal mines, quiet diesel submarines and small, fast, armed boats.
If we put this into context, it's a fairly small scale of deployment and the combat ships are relatively small vessels, said Euan Graham, senior fellow in the Maritime Security Programme at Singapore's S. Rajaratnam School of International Studies.
Encirclement is a phrase that does come up in Chinese debate about the U.S. strategy. They won't be happy about it, but there's nothing much that they can do to stop it.
Greenert wrote the ships would focus on the South China Sea, conducting operations to counter piracy and trafficking, both of which are endemic in the area.
Similarly, 2025 may see P-8A Poseidon aircraft or unmanned broad area maritime surveillance aerial vehicles periodically deploy to the Philippines or Thailand to help those nations with maritime domain awareness.
One source briefed on navy plans said there has also been discussion about stationing ships in the Philippines.
The disputed ownership of the oil-rich reefs and islands in the South China Sea is one of the biggest security threats in Asia. The sea is claimed wholly or in part by China, Taiwan, the Philippines, Malaysia, Vietnam and Brunei.
The shortest route between the Pacific and Indian Oceans, it has some of the world's busiest shipping lanes. More than half the globe's oil tanker traffic passes through it.
Obama told Chinese Premier Wen Jiabao at a regional summit in November that the United States wanted to ensure the sea lanes were kept open and peaceful. Wen was described by U.S. officials as being grouchy later at the summit, when other Asian countries aligned with Washington.
The Chinese premier said outside forces had no excuse to get involved in the complex maritime dispute, a veiled warning to the United States and other countries to keep out of the sensitive issue.
A modest marine presence in Australia - 2,500 marines is not a large offensive force by any means - and ships in Singapore do not mean it's all about China, Paul Dibb, the head of the Strategic and Defence Studies Centre at the Australian National University, told Reuters.
But having said that, China is being increasingly assertive on the high seas. So while I don't see the U.S. as encircling China, it would be silly to say China wasn't part of it.
These developments on the littoral combat ships (LCS) are being closely watched by Lockheed Martin Corp, Australia's Austal, General Dynamics Corp and other arms makers that are building two models of the new warships for the U.S. Navy, and hope to sell them to other countries in coming years.
Because we will probably not be able to sustain the financial and diplomatic cost of new main operating bases abroad, the fleet of 2025 will rely more on host-nation ports and other facilities where our ships, aircraft, and crews can refuel, rest, resupply, and repair while deployed, Greenert wrote in the naval magazine.
Ernie Bower, who is with the Centre for Strategic and International Studies, said the emerging strategy for Southeast Asia would be far different from the big U.S. bases established in Japan and South Korea in the past.
We're exploring a new arrangement with a smaller footprint, that is mission-specific, and culturally and politically more palatable to countries, he said, adding it would be difficult for Washington to drum up much political support for big bases in the region. Forward-stationing versus permanent bases would also save the navy money, he said.
Greenert did not provide a timetable for the LCS stationing in Singapore.
In the Philippines, a U.S. ally that has clashed several times with China over the South China Sea dispute, the moves were welcomed.
We're together in Asia Pacific and we face common security challenges, said defence spokesman Peter Paul Galvez.
We see several security challenges where we actually need inter-operability and interplay exercises including disasters, threats of terrorism, freedom of navigation, piracy and human trafficking. We cannot deny that we need their assistance in that aspect. (Additional reporting by Rob Taylor in Canberra and Manuel Mogato in Manila; Editing by Raju Gopalakrishnan and Alan Raybould)