The Pentagon is reportedly extending a pilot program designed to protect its prime defence contractors form cyber attacks.

There have been a growing number of cyber attacks on defence contractors in recent months. The most high profile attack was on fighter planes and spy satellites maker Lockheed Martin in June this year. The security breach in its network two weeks ago was carried out by hackers partly by using data stolen from computer security company EMC’s RSA division.

Now the Pentagon project comes as analysts warn that more and increasingly sophisticated cyberattacks are anticipated against US defense companies, said an AP report. Analysts have also repeatedly warned that critical systems of the country are also under threat.

The report said that officials at the Department of Homeland Security are reviewing the program, with an aim to extending similar protections to power plants, the electric grid and other critical systmes.

"The results this far are very promising," said William Lynn, the deputy secretary of defence.

"I do think it offers the potential opportunity to add a layer of protection to the most critical sectors of our infrastructure."