Around 4,000 defence workers are set to lose their jobs after US contractor Lockheed Martin announced on Thursday it was looking for ways to cut costs.

"In the face of government budget cuts and an increasingly complex global security landscape, these actions are necessary for the future of our business," CEO Marilyn Hewson claimed.

Across-the-board spending cuts by the federal government have been used in the last year to trim US budget deficits.

Budget negotiators in Congress are holding talks centred on finding ways to cut spending and tax breaks in order to replace the automatic cuts that started earlier this year.

Maryland-based Lockheed Martin will close plants in Goodyear in Arizona, Akron in Ohio, Newtown in Pennsylvania and Horizon City in Texas, as well as four buildings at its Sunnyvale, California campus, by mid-2015, eliminating at least 2,000 jobs.

And another 2,000 positions will be cut in its information systems and global solutions, mission system and training, and space systems units by the end of 2014.

The firm said it would shift work and some employees to facilities in Denver and Valley Forge, Pennsylvania.

Lockheed Martin has cut its workforce from 146,000 to 116,000 employees since 2008.

Company shares have risen by 49 per cent this year as third-quarter profit surged to $873 million (£542m), up from $727m (£451m), a rise of 15 per cent.

The company expects consolidated operating profit ranging from $4.6 billion (£2.8bn) to $4.7bn (£2.9bn) for the full year.