It based its findings primarily on a survey of eight ranges and the military's own studies. The military has 70 major training ranges, including some at sea, the report says.

In its report, the GAO says "military training ranges are in varying degrees of degradation or lack necessary upgrades to meet current training needs, a condition that, in turn, adversely affects training activities and jeopardizes the safety of the military personnel using them."

For example, at Fort Hood, Texas, home to tens of thousands of soldiers, GAO investigators found degraded tank trails, too few sniper and machine gun ranges and a training area for urban operations that is geared for preparing soldiers to fight in the narrow streets of Eastern Europe rather than the walls and courtyards of Middle Eastern cities.

At the Navy's Southern California Offshore Range, a malfunctioning communications system has rendered much of the range useless for submarines.

And the Fallon Range Training Complex in Nevada, where Navy pilots train, "lacks adequate systems to replicate current threats and targets.

It lacks advanced surface-to-air missile threat systems and has an inadequate concentration of electronic warfare systems," the GAO says.