However, military budget analysts said the cuts, which would return the Pentagon base budget to 2007 levels, would be painful but manageable, The New York Times reported Wednesday.
The $500 billion in cuts spread over 10 years beginning in 2013, triggered by the failure Monday of the Joint Committee on Deficit Reduction to reach a deal to cut at least $1.2 trillion from the deficit, are on top of $450 billion in spending reductions over the next decade that the Defense Department and the White House agreed to last summer.
Defense Secretary Leon Panetta described the $450 billion reduction as painful but acceptable.
The Pentagon said the automatic cuts would reduce the 2013 budget by 23 percent and was the reason why Defense officials said they would push Congress to come up with a way to avoid sequestration, the automatic cuts triggered by the panel's failure.
"We are not planning for the sequester," Pentagon spokesman Doug Wilson said. "The focus is on trying to get Congress to do what it said it would do" to protect the department.
While closing bases, reducing the size of the Army and laying off civilian employees reduces spending over time, he said, the fastest way to reduce the budget is to cut funding for major weapons systems, something Panetta's predecessor, Robert Gates, began.
"The Pentagon has been cutting weapons programs by hundreds of billions of dollars for three years now," Loren B. Thompson, a consultant to military contractors, told the Times. "There's not much left to kill that won't affect the military's safety or success."
The failure of the supercommittee to reach agreement also offers another campaign issue for the 2012 presidential election, giving the eventual Republican nominee a chance to stump for reversing the automatic cuts, Roll Call said.
"It was a very bad idea to put our national security on the chopping block, and [I] will, if elected president, reverse those cuts," former Massachusetts Gov. Mitt Romney said last week in a radio interview.
Former House Speaker Newt Gingrich, who ripped the supercommittee since it was conceived, repeatedly said he would not honor its directives. Campaign spokesman R.C. Hammond said Monday Gingrich would work to reverse the defense cuts if elected president and also hinted Gingrich would reconsider reversing or reapportioning the triggered cuts to social programs.