The figures, covering the 2006-12 period, come from the National Center for Defense Robotics, a congressionally funded consortium of 160 companies, and were reported by analyst David Isenberg in the Asia Times Tuesday.

Isenberg writes that the U.S. military has already deployed thousands of robot systems in Iraq and Afghanistan, including the 40-pound PackBot -- a miniature tank equipped with a video camera. Made by the iRobot Corp., which manufactures the Roomba, the home vacuum-cleaning robot, the PackBot “can climb stairs, penetrate caves, and peek around corners … so that troops can reconnoiter while avoiding the enemy as well as booby traps,” writes Isenberg.

He says that the military has now begun deploying armed remote-controlled robot systems, like the Special Weapons Observation Remote Reconnaissance Direct Action System. “The SWORDS is armed with an M249 rifle and is remotely controlled by a soldier,” writes Isenberg, noting, “There are no reports of the SWORDS being used in actual combat yet.”

Isenberg points out that, at present, international law forbids the automatic operation of armed robot systems: “Unmanned systems cannot fire their weapons without a human operator in the loop.”

But he predicts there will be pressure to change that as the capabilities of robot systems grow, and notes that, in 2002, a senior military lawyer proposed that robots be programmed to fire at weapons, rather than people, to get around the law.