The Pentagon has begun laying off many of its 46,000 temporary and contract workers and delaying maintenance on aircraft and ships to slow spending due to fears it may be hit by new budget cuts, Deputy Defense Secretary Ashton Carter said on Friday.

The Pentagon also plans to formally notify Congress in the next few weeks that if further budget cuts take place on March 1, it will furlough most of its 800,000 full-time civilian employees, probably by asking them to take a day off per week for the last 22 weeks of the fiscal year, Carter said.

“Obviously this is a terrible thing to have to do to our employees and to the mission,” Carter said. “But it’s necessary because it’ll save $5 billion and we have to find that money.”

The cost-cutting steps come as the Pentagon tries to deal with budget uncertainty caused by the threat of $45 billion in across-the-board spending reductions on March 1 and Congress’s failure to appropriate defense funding for the 2013 fiscal year.

The Pentagon currently is absorbing $487 billion in cuts to projected defense spending over 10 years that were agreed in the Budget Control Act of 2011. That law also required the additional across-the-board cuts by Jan. 1, 2013, unless Congress agreed to an alternative.

Lawmakers failed to reach a new deal but did agree to postpone the across-the-board cuts until March 1 to give themselves more time. But March 1 is five months into the fiscal year, giving the Pentagon less time to absorb any cuts.

Defense officials had long resisted taking action in response to the threat of additional reductions, saying they were put in place to try to force Congress to reach an alternative.

But Carter said the congressional debate on U.S. financial issues in late December had been sobering, with little discussion of how cuts would affect the Pentagon or its mission. Postponing the decision for another two months reduced the time the department would have to respond.