Over the past four years, 17 soldiers have died in friendly fire incidents such as the one that killed former professional football player Pat Tillman, according to Army data.
The 17 soldiers felled by friendly fire incidents are about 1 percent of the 1,575 soldiers who have died overall. More than 2,500 troops from all services have died in the two conflicts.
The 1 percent rate is well below that of Operation Desert Storm when 17 percent of all service members who died were killed by friendly fire. Rates for World War II, Vietnam and the invasions of Grenada and Panama were also higher than the Iraq and Afghanistan conflicts.
So far, the 2004 death of Tillman, an Army Ranger and corporal, during a firefight near the Pakistan-Afghanistan border has been the only one in the war to trigger a formal criminal investigation. Army officials said its Criminal Investigation Command has reviewed other incidents, and there have been some reprimands or administrative punishments handed out.
Officials said they could not provide details on those reprimands, including how many there have been.
Of the 17 deaths caused by U.S. or other coalition allies, 10 were in Iraq and seven in Afghanistan. They occurred in 11 separate incidents.
The information the Army provided Friday consisted of numbers, not names of those killed or details of the incidents. Identities of the victims of friendly fire have been previously reported.
Pentagon spokesman Paul Boyce said friendly fire deaths have declined due to increased training, better leadership and new technology that makes it easier to identify forces.
For example, a small, thumbprint-size square of reflective material is embedded into the upper portion of soldiers' sleeves and allows others to identify them as U.S. troops.
Army officials say today's more lethal weapons, difficult battlefields and rapid-paced engagements are most often the cause of friendly fire deaths.
"Combat is highly complex and stressful," Boyce said. "Operations are conducted 24 hours a day, in all types of terrain and weather."
Boyce said that in addition to intense engagements with weapons being fired from air, land and sea, "soldiers become fatigued and equipment can malfunction. These and other occurrences produce what is called the fog of war."
The rate of friendly fire deaths for all U.S. troops in World War II was 12-14 percent; Vietnam, 10-14 percent; Grenada, 13 percent; and Panama, 6 percent.
The Tillman family's outspoken and anguished reaction to his death contributed to the military's decision to probe the matter further. Last week the Army launched a criminal investigation into Tillman's killing, and the Defense Department said its inspector general is looking into allegations of a cover-up.
The investigation will review the Army's failure to tell Tillman's family for several weeks that he was killed by gunfire from his fellow Rangers, not the enemy as they were initially told.
Tillman's shooting wasn't the first time in the Iraq war that the military initially failed to acknowledge that a death was the result of friendly fire.
It took nine months for the family of Army Spc. Jesse Buryj of Canton, Ohio, to learn that his death in Iraq in May 2004 was not the result of an accidental vehicle crash as they were first told. He was killed by fire from U.S. or Polish soldiers in Karbala after a dump truck hurtled through a checkpoint and crashed into the armored vehicle in which he was riding.