U.S. troops vulnerable to enemy drones.

U.S. forces deployed in the Middle East need improved defenses against unmanned drones, says the Army's top general in charge of air-defense systems. While fighting Israeli forces this summer, Lebanon's Hezbollah guerillas demonstrated their ability to deploy armed drones. These aircraft could strike U.S. forces rather easily, because they might be confused with friendly aircraft, says Maj. Gen. Robert P. Lennox, head of the Army Air Defense Artillery Center. A case in point is Iran's Ababil-T, which is not technologically advanced by U.S. standards, but could be mistaken as a friendly UAV. "How do you discern if it's a friendly UAV coming home, or one trying to strike?" Lennox asks. "That's a challenge."

In the Army, he says, "We need to start thinking about how to deal with the enemy UAVs." The Patriot missile-defense system can take down UAVs, but each Patriot round costs $3 million. "You want a system that is commensurate with the target," says Lennox. Armed UAVs can be built for as little as $3,000.

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