The hacking was possible because the remotely flown planes have an unprotected communications link.
Obtaining such video feeds could provide insurgents with information about sites the military might be planning to target.
The Associated Press news agency quotes a US Department of Defense official as saying the military has also found evidence of at least one instance where insurgents in Afghanistan monitored drone video.
The breach of the Pentagon surveillance system's security in Iraq is said to have come to light when footage shot by a Predator drone was found on the laptop of an apprehended insurgent.
A senior Pentagon official is quoted by the Wall Street Journal as saying that although militants were able to view the video, there was no evidence that they were able to jam electronic signals from the aircraft or take control of them.
The unnamed official said the US defence department had addressed the issue by working to encrypt all video feeds provided by drones in Iraq, Afghanistan and Pakistan. Predator drones can fly for several hours, remotely controlled by pilots thousands of miles away. The aircraft can carry out surveillance and attack targets with on-board missiles.
Responding to the reports, a Pentagon spokesman said: "The Department of Defense constantly evaluates and seeks to improve the performance and security of our various systems and platforms.
"As we identify shortfalls, we correct them as part of a continuous process of seeking to improve capabilities and security. As a matter of policy, we don't comment on specific vulnerabilities or intelligence issues."
Source: BBC News
So if the live feed can be monitored by using a simple software, why couldn't they monitor the feeds of the reconnaissance missions, and somehow, get the area where the drone was targetting, warn everybody in the vicinity, move their stuff out of their houses, save their books if that location was a madressah...and......
*huge sigh*... Dream on. Yeah.