|Panetta, at right, has vowed to meet with congressional leaders 'to make common-sense cuts'
Leon Panetta, the US defence secretary, has cautioned that any across-the-board cuts to defence spending as part of the next stage of deficit reduction efforts could inflict "real damage" to the country's national security.
He said in a statement on Thursday that a potential second round of cuts in security spending estimated at about $600b from 2012 to 2021 would be "completely unacceptable".
He said it was not acceptable "because we live in a world where terrorist networks threaten us daily, rogue nations seek to develop dangerous weapons, and rising powers watch to see if America will lose its edge.
"If that happens, it could trigger a round of dangerous across-the-board defence cuts that would do real damage to our security, our troops and their families, and our ability to protect the nation".
Panetta vowed to work with congressional leaders "to make the common-sense cuts needed to avoid this sequester mechanism".
A senior US official, speaking on the condiction of anonymity, said that such sweeping cuts would require dismissing thousands of defence department personnel, disrupt arms programmes and probably cut $50bn to $60bn, roughly 10 per cent, from the Pentagon's budget per year.
This would be on top of about $350bn in security spending savings in the first phase of a deficit-cutting
package signed into law on Tuesday by President Barack Obama in a deal to lift country's $14.3tn debt ceiling.
Mike Mullen, chairman of the joint chiefs of staff, said he expected much of the budget cut to fall on weapons
systems that the Pentagon is developing or planning to buy.
"We've got to take care of our people. We've got to fund the fights that we're in," he said.
"I think a significant part of the stuff that we buy, that slows down or gets eliminated. Poor performing programmes, I think, will be killed," he said in Baghdad, Iraq's capital, on Tuesday,
Private budget analysts have called for cutting or cancelling some of the military's costly weapons programmes.