The Predator operators reported seeing only military-age men in the truck, the report said. The ground commander concurred, the report said, and the Special Operations team asked for an airstrike. An OH-58D Kiowa helicopter fired Hellfire missiles and rockets, destroying the vehicles and killing 23 civilians. Twelve others were wounded.

Image Credit... The New York Times

The report, signed by Maj. Gen. Timothy P. McHale, found that the Predator operators in Nevada and “poorly functioning command posts” in the area failed to provide the ground commander with evidence that there were civilians in the trucks. Because of that, General McHale wrote, the commander wrongly believed that the vehicles, then seven miles away, contained insurgents who were moving to reinforce the fighters he and his men were tracking.

“The strike occurred because the ground force commander lacked a clear understanding of who was in the vehicles, the location, direction of travel, and the likely course of action of the vehicles,” General McHale wrote.

The “tragic loss of life,” General McHale found, was compounded by the failure of the ground commander and others to report in a timely manner that they might have killed civilians.

Predator drones and similar aircraft carry powerful cameras that beam real-time images to their operators, and some are armed with missiles, as well. The C.I.A. operates its own drone operation, mostly focused on Pakistan and separate from the military’s.

In this case, the military Predator operators in Nevada tracked the convoy for three and a half hours, but failed to notice any of the women who were riding along, the report said.

According to military officials in Washington and Afghanistan, who spoke on the condition of anonymity because they were not authorized to brief reporters on the case, intelligence analysts who were monitoring the drone’s video feed sent computer messages twice, warning the drone operators and ground command posts that children were visible.