Washington, April 21 (Inditop) Computer spies have broken into the US Defence

Department’s costliest weapons programme ever, the $300 billion Joint Strike Fighter project, the Wall Street Journal reported Tuesday.

Similar incidents have also breached the Air Force’s air traffic control system in recent months, it said citing unnamed “current and former government officials familiar with the attacks.

“In the case of the fighter jet programme, the intruders were able to copy and siphon off several terabytes of data related to design and electronics systems, officials were quoted as saying, potentially making it easier to defend against the craft.

Many details couldn’t be learned, including the specific identity of the attackers, and the scope of the damage to the US defence programme, either in financial or security terms, the Journal said.

In addition, while the spies were able to download sizable amounts of data related to the jet fighter, they weren’t able to access the most sensitive material, which is stored on computers not connected to the Internet, it said.

Former US officials cited by the Journal said the attacks appear to have originated in China. However, it can be extremely difficult to determine the true origin because it is easy to mask identities online. The Joint Strike Fighter, also known as the F-35 Lightning II, is the costliest and most technically challenging weapons programme the Pentagon has ever attempted.

The plane, led by Lockheed Martin Corp., relies on 7.5 million lines of computer code, which the Government Accountability Office said is more than triple the amount used in the current top Air Force fighter. The Journal said six current and former officials familiar with the matter confirmed that the fighter programme had been repeatedly broken into. The Air Force has launched an investigation.

The intruders entered through vulnerabilities in the networks of two or three contractors helping to build the high-tech fighter jet, it said citing people who have been briefed on the matter.

Pentagon officials declined to comment directly on the Joint Strike Fighter compromises. Pentagon systems “are probed daily”, Air Force Lt. Col. Eric Butterbaugh, a Pentagon spokesman, was quoted as saying.

Joint Strike Fighter test aircraft are already flying, and money to build the jet is included in the Pentagon’s budget for this year and next.