"Our investigation now concludes the strike was a tragic mistake," Marine Gen. Frank McKenzie, chief of U.S. Central Command, said Friday.
U.S. forces launched the strike after they had tracked a white Toyota Corolla for eight hours and deemed it an imminent threat, McKenzie said. There had been more than 60 pieces of intelligence at the time that indicated an attack was coming, he said. As many as six Reaper drones had followed the vehicle, he added.
The strike occurred on Aug. 29 near the airport during the final, chaotic days of the U.S. evacuation of civilians and military retreat from Afghanistan. The military claimed at the time that the strike prevented "multiple suicide bombers" from attacking Hamid Karzai International Airport. The statement from U.S. Central Command said the attack had targeted "an imminent ISIS-K threat" and that explosives were being loaded into the vehicle when the Hellfire missile struck it.
US Defense Secretary Lloyd Austin apologized to the relatives of those killed in a statement.
"I offer my deepest condolences to surviving family members of those who were killed," Austin said in a statement.
"We apologize, and we will endeavor to learn from this horrible mistake," he said.
McKenzie said the government was studying on how payments for damages could be made to the families of those killed.
White Toyota Corolla
The general said that on August 29 US forces had tracked a white Toyota for eight hours after seeing it at a site in Kabul that intelligence had identified as a location from which Islamic State operatives were believed to be preparing attacks on the Kabul airport.
Intelligence reports had led US forces to watch for a white Toyota Corolla that the group was allegedly using, he said.
"We selected this car based on its movement at a known target area of interest to us," McKenzie said.
"Clearly our intelligence was wrong on this particular white Toyota," he said.
The drone strike killed 10 people, including seven children, according to McKenzie, none of who ultimately were linked to IS.
McKenzie defended the US operation as in "self-defense strike" amid concerns about an attack on the airport in the last days of the chaotic evacuation.
On August 26 an Islamic State-Khorasan suicide bomber had killed scores at the airport, including 13 US service members. Huge crowds were there clamoring to get inside and on board one of the final evacuation flights out of the country.
"There were over 60 clear threat vectors that we were dealing with at this time," McKenzie said.
One of those killed was an Afghan man who worked for a US aid group, Ezmarai Ahmadi.
"We now know that there was no connection between Mr. Ahmadi and ISIS-Khorasan," said Austin.
He said Ahmadi's activities that day were "completely harmless," and that the man was "just as innocent a victim as were the others tragically killed."
"On behalf of the men and women of the Department of Defense, I offer my deepest condolences to surviving family members of those who were killed, including Mr. Ahmadi, and to the staff of Nutrition and Education International, Mr. Ahmadi's employer," Austin said.