It looks like the federal budget sequester is finally beginning to bite Lockheed Martin (NYSE:LMT).

On Thursday, the nation's biggest defense contractor announced plans to "close and consolidate" several U.S. facilities, laying off 4,000 workers in the process. In a statement, Lockheed directly attributed the move to "continued declines in U.S. government spending," necessitating a move to improve operational efficiency.

Over the next two years, Lockheed plans to completely shutter operations in Newtown, Pa.; Akron, Ohio; Goodyear, Ariz.; and Horizon City, Texas; and shut down four buildings on its Sunnyvale, Calif., campus. Two thousand jobs will be lost at facilities to be closed by mid-2015. The balance of the layoffs will come from positions being eliminated globally in the company's information systems and global solutions, mission system and training, and space systems divisions. These latter layoffs should be complete by the end of 2014.

Even as many cities are hurt by the closures and layoffs, a few cities may actually benefit. Lockheed said that workers who are relocated as a result of the consolidation will be moved to locations in Denver and Valley Forge, Pa. Lockheed facilities in Owego, N.Y., and Orlando, Fla., may also see an influx of transferred workers.

Since the financial crisis broke in 2008, Lockheed has reduced its workforce by more than 20%, from 146,000 employees to 116,000. Today's announcement heralds a further reduction of about 3.4%.