The United States hopes to build an alliance with friendly navies such as India's to form a global force of 1,000 ships and boost maritime security, a top US naval commander said on Friday.
But Washington's naval cooperation with New Delhi is not intended to send a signal to Beijing and the US navy was not looking to build a base in the Indian Ocean region, Vice-Admiral Doug Crowder said.
The comments by Crowder, commander of the Seventh Fleet, came midway through wargames involving five nations, led by the United States and India, in the Bay of Bengal, one of the biggest such peacetime exercises which has raised the hackles of China.
"We all have common interests in keeping the oceans of the world open, free for commerce," Crowder told reporters on board the US aircraft carrier Kitty Hawk. "But the United States navy just isn't large enough to do that."
"We have to find common cause and every nation's sovereignty is protected. They join us for those missions they have a common interest in ... anti-piracy, humanitarian relief, security of the sea lanes."
The six-day wargames which began on Tuesday, involving nearly 30 ships and over 100 aircraft, is the latest in a series called the "Malabar Exercise", first held in the mid-1990s between Indian and US forces.
India's navy now has around 140 ships, compared with about 280 in the US navy.
This year the drill has been expanded to include a few ships from Australia, Japan and Singapore in what some analysts see as a new alliance of democracies ranged against the growing military might of China.
Although top officials from countries involved in the wargames have assured Beijing that it is not the focus of the exercise, China remains concerned by what it sees as a new security alliance that aims to encircle it.
"Asian powers coming together"
Crowder sought to once again underplay the strategic significance of the wargames, held not far from a Myanmar island where China is believed to have a military listening post.
"This was not put together as a signal against anyone," Crowder said.
Relations between Washington and New Delhi, on opposite sides of the Cold War, have blossomed since the turn of the last century.
As India's military, the world's fourth largest, goes on a modernising spree, it stood to gain from the United States, Indian officers said.
"We cannot be like frogs in the well and think that we know everything," said Indian Vice-Admiral Raman Prem Suthan. "It's a changing world and we are looking at professional interaction."
While Suthan also tried to sidestep the political undertones of the wargames, analysts said there was no mistaking their strategic underpinning.
The drill coincides with a summit of Asia-Pacific leaders in Sydney this week and a trilateral security dialogue on its sidelines between US President George W Bush, Australian Prime Minister John Howard and Japanese premier Shinzo Abe.
All three countries have in recent months expressed concern at what they say is China's soaring military spending and a lack of transparency about its defence strategy.
Although India-China ties have warmed significantly over the back of booming trade since a border war in 1962, they are yet to settle their frontier dispute and continue to eye each other with some mutual suspicion.
China in March said it would boost defence spending by 17.8 per cent to about $45 billion this year, but a Pentagon report in May said Beijing's total military-related spending could be more than double that.
"This is a major coalescing of Asian powers, indicating greater cooperation," said Walter Andersen, a former US State Department analyst who is now at the Johns Hopkins School of Advanced International Studies.
He said both New Delhi and Washington were being careful not to portray the wargames as being anti-Chinese.
"But it provides leverage to keep them concerned about what can happen, that is, 'if you get too nasty with us, we always have friends elsewhere'," he said.
(Additional reporting by Paul Eckert in Washington)