Cyber hackers nearly two years ago breached a high-tech jet fighter program developed for the Pentagon by Lockheed Martin Corp., but classified information was not compromised, a senior defense official said Tuesday. No details about the attacks were provided. The defense official spoke on condition of anonymity because of the sensitive nature of the issue. In confirming the attack on Lockheed's F-35 Lightning II program, also known as the Joint Strike Fighter, the defense official said it is unclear who did it, or whether it was an attempt at corporate thievery or a hacker trying to harm the program. The Pentagon is expected to pay about $300 billion to buy nearly 2,500 of the F-35 jets for the Air Force, Navy and Marines.