WASHINGTON - Insurgents in Iraq and Afghanistan have intercepted live video feeds from Predator drones, a key weapon in a Pentagon spy system that serves as the military's eyes in the sky for surveillance and intelligence collection.

Though militants could see the video, there is no evidence they were able to jam the electronic signals from the unmanned aerial craft or take control of the vehicles, a senior defense official said yesterday, speaking on condition of anonymity to discuss sensitive intelligence issues.

Obtaining the video feeds can give insurgents critical information about what the military may be targeting, including buildings, roads, and other facilities.

Shiite fighters in Iraq used off-the-shelf software programs such as SkyGrabber - available online for as little as $25.95 - to regularly capture drone video feeds, the Wall Street Journal reported yesterday. The interception, first done there at least a year ago, was possible because the remotely flown planes had unprotected communications links.

Within the last several months, the military has found evidence of at least one instance in which insurgents in Afghanistan also monitored U.S. drone video, a second defense official said. He had no details on how many times it was done in Afghanistan or by which group.

The Defense Department has addressed the issue, and is working to encrypt all its drone video feeds from Iraq, Afghanistan, and Pakistan, defense officials said. One defense official noted that upgrading the encryption in the drones is a lengthy process because there are at least 600 unmanned vehicles along with thousands of ground stations to address.

Systems in key threat areas were upgraded first, officials said.

Dale Meyerrose, former chief information officer for the U.S. intelligence community, likened the problem to that of street criminals listening to police scanners.

"This was just one of the signals, a broadcast signal, and there was no hacking. It is the interception of a broadcast signal," said Meyerrose, who worked to field the unmanned systems in the 1990s, when he was a senior Air Force officer.

The problem, he said, is that when the drones were first being developed, they were using commercial equipment, which as time goes on could become vulnerable to intercepts.

The Predator, also being used in the hunt for al-Qaeda and other militants in Pakistan, Somalia, and elsewhere, can fly for hours remotely controlled by pilots thousands of miles away. It can fly armed or unarmed, and is part of a growing arsenal of such craft that includes the Reaper and Raven and a new, high-tech video sensor system called the Gorgon Stare, being installed on Reapers.

The military has known about the vulnerability for more than a decade, but it assumed adversaries would not be able to exploit it.

Then, last December, the military apprehended a Shiite militant in Iraq whose laptop contained files of intercepted drone video feeds, the Journal reported. In July, they found pirated feeds on other militants' laptops, leading some officials to conclude that groups trained and funded by Iran were regularly intercepting feeds and sharing them with multiple extremist groups.

Defense Secretary Robert M. Gates asked the Pentagon's intelligence chief, James R. Clapper, Jr., to look into the problem and coordinate the work to address it. Officials said that when the intercepts were discovered in July 2008, it raised concerns, but that technical adjustments were not difficult and were put in motion quickly.

Pentagon spokesman Bryan Whitman said the military continually evaluates the technologies it uses and quickly corrects any vulnerabilities found.