Beijing should not fear a new US defence policy, seen as an "evolutionary" Asian security strategy to counterbalance China's growing might, that will lead to a network of new military partnerships across Asia, officials and analysts said on Friday.
The new defence strategy, which will expand the US military presence in Asia but shrink the overall size of the force in order to slash defence spending, was flagged late last year and is a clear sign of US commitment to the region.
Beijing, however, is concerned Washington's new defence posture, as it turns away from wars in Iraq and Afghanistan, is aimed at encircling China and could hobble its growing power.
Australia, a close US military ally and already engaged in a A$65 billion defence buildup, said the rebalancing of US forces to Asia should not threaten China, or Australia's A$113 billion two-way trade relationship with Beijing.
"The American position is very sophisticated and it's sophisticated in directions we'd encourage. It's not a containment strategy," Australia's Washington ambassador, former defence minister Kim Beazley, told Australian radio.
Obama unveiled the new strategy on Thursday, saying the "tide of war is receding".
US defense secretary Leon Panetta said the military would be "smaller and leaner".
Administration officials say they expect the Army and Marine Corp to be cut by 10% to 15% over the next decade.
Washington has said it will seek to work with China to ensure economic prosperity and security in the region but would continue to raise security issues like the South China Sea, through which $5 trillion dollars in trade sails annually.
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.
China is seen as increasingly assertive on the high seas, with several incidents in the South China Sea in the past year.
China's missiles raise concerns
There is also growing concern in the United States and Asia at China's military developments in recent years, both in the size of its force and its capabilities, said security analyst Ross Babbage at Australia's Kokoda Foundation.
China has been expanding its naval might, with submarines and a maiden aircraft carrier, and has also increased its missile and surveillance capabilities, extending its offensive reach in the region and unnerving its neighbours.
"In the last three to four years there has been the deployment of very large numbers of missiles, ballistic and cruise, and also the refining of surveillance capabilities," Babbage said.
Under the new defence strategy, the US will maintain its large bases in northern Asia, in Japan and South Korea.
Lim Kwan-bin, deputy minister for National Defence Policy at the South Korean defence ministry, told a news conference in Seoul on Friday Washington officials had assured him the new strategy "will have no impact" on US forces in South Korea.
Tensions have risen considerably on the Korean peninsula, the most militarised area in the world, after the death of Kim Jong-il on Dec 17 ushered in new uncertainty about the leadership of the unpredictable communist state.
Tokyo also saw little direct impact from Washington's defence shift and welcomed the new strategy, Kyodo news agency quoted Japanese defence minister Yasuo Ichikawa as saying.
Washington is under pressure to close its main Marine base in Okinawa.
"What we are seeing is the development and growth of a network of partnerships to strengthen capabilities and resilience," Babbage said.
Beazley, an expert on US defence policy, identified potential border disputes as especially important and said Australia would be heavily affected by the new American focus on maritime resources and the Asia-Pacific region.
"It is America underpinning ... a resolution of any border conflicts, and maritime border conflicts are particularly important in the Southeast Asian area," said Beazley.
During a visit to Australia last November, Obama announced Marines, naval ships and aircraft will be deployed to northern Australia from 2012, using Darwin as a de facto base.
The deployment to Australia, which will reach a taskforce of 2,500 US troops by 2016, is small compared with the 28,000 troops stationed in South Korea and 50,000 in Japan.
However, the United States will likely use Darwin as a model for deploying its military, especially air and naval assets.
The US Navy has said it will station several new coastal combat ships in Singapore and perhaps the Philippines in coming years.