The workers, most of whom signed up for a voluntary job buyout program, will be gone by Dec. 14, the company said.
Northrop employs 21,000 workers in its aerospace division, most of them in Southern California, the Los Angeles Times reported.
"Because of defense budget uncertainties and pressures on current and projected business, we must adjust our budgets by the end of this year to be prepared to meet the challenges of what shapes up as a demanding 2013," company spokesman Thomas Henson said in a statement.
"This is a necessary step to address the affordability that will allow us to effectively compete in a very cost-conscious marketplace," the statement said.
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