The U.S. military has given troops in Iraq a laser device to temporarily blind drivers who ignore warnings at vehicle checkpoints, the Pentagon said on Thursday.

Army Lt. Col. Barry Venable, a Pentagon spokesman, defended its use as legal and said the devices were intended to prevent civilians from being shot.

"There have been numerous incidents that tragically have resulted in civilian deaths" in which drivers approaching U.S. military checkpoints have failed to heed warnings from troops, who in some cases have opened fire, he said.

The U.S. military is fitting some M-4 rifles used by U.S. forces in Iraq with a tube-shaped device that is about 10 1/2 inches (27 cm) long that shines a laser beam. Venable stressed that the devices do not cause permanent blindness.

"They don't blind people. It's like shining a big light in your eyes," Venable said. "I think the term is optical incapacitation -- dazzlers as opposed to something that will blind you."...