The American fiscal crisis risks ensnaring the military with drastic cuts and strategic changes that the army fears will leave it the main victim of the country's debt crunch, analysts said.

Having almost doubled since 2001, the Pentagon budget request to Congress will amount to $553 billion in 2012, on top of $118 billion allocated by the White House for operations in Iraq and Afghanistan eight months ago.

But a deficit reduction plan passed since those monies were allocated will strip around $450 billion from military coffers over the next decade.

General Ray Odierno, the army's chief of staff, said in Washington on Monday that the savings can be achieved, but not without serious implications.

"Those are difficult, difficult cuts that have an impact on all the services, but particularly, in my mind, on the army," he said.

The sticking point is that budget planners and strategists at the Pentagon cannot yet determine what programs or weapons will be cut or how many personnel will be declared redundant.

Further cost-savings of up to $600 billion could come as a result of a bipartisan commission in Congress tasked with finding additional ways to reduce federal spending by the end of November.

William Lynn, who was deputy defense secretary, warned when he left office last week that such large cuts would require "difficult choices" and a combination of drastic measures.

"We can do this by bringing overall force levels down as we draw down in Afghanistan. We can reduce our presence in some parts of the world while maintaining or expanding it in others," he said.

"And we can leverage technology to make a smaller force more effective and agile than the force we have today, but we will have to modify our strategy and prioritize our key missions."

Having risen from 480,000 active soldiers in 2001 to 570,000 currently, US army numbers will probably fall below 520,000 after withdrawals from Iraq at the end of this year and from Afghanistan in 2014, Odierno has said.

Former lieutenant general David Barno, now an analyst at the Center for a New American Security (CNAS) think tank in Washington, said the army could be the big loser, as it is easier to cut soldiers than end naval or air programs.

"Cutting the number of ground forces may incur less risk than canceling naval and air modernization programs because the US military can build up additional ground forces more quickly than it can acquire additional naval and air forces once production lines have closed," he said.

Despite the doubling of the defense budget since 2001, the United States has fewer ships and aircraft than it had a decade ago, and they are all older, according to a study by National Security Network, another think tank.

Future savings should therefore be accompanied by refocusing strategy to address potential threats to the United States, according to Barno, who pointed to China's moves to extend its reach in the Pacific.

Such a change could be achieved by technological advances, developing longer-range air strike capacity, increasing the use of drones and stealth warfare, and reducing the 43,000 US troops still stationed in Europe.

But John McHugh, secretary of the army, said it was wrong to think that future conflicts could be fought without ground troops.

"No major conflict has ever been won without boots on the ground," he said, hitting out at "columnists, analysts, part-time critics and talking heads" who think the United States does not need "a strong and decisive standing army."

"The future to them looks more like 'Transformers' than 'Saving Private Ryan'," McHugh said.