A U.S. drone strike in Kabul that killed 10 civilians, including seven children, was conducted after numerous miscalculations by commanders who wrongly believed an aid worker was hauling explosives in his car, defense officials said Friday, reversing the Pentagon’s earlier insistence that the operation prevented an imminent suicide attack on U.S. forces.

The Defense Department had previously defended the Aug. 29 operation as a “righteous strike,” saying it tracked a white sedan for hours after the vehicle left a suspected Islamic State-Khorasan safe house. In fact, the driver, Zamarai Ahmadi, was a longtime aid worker for a U.S.-based group and was hauling water cans for his family, officials acknowledged.

“We now know that there was no connection between Mr. Ahmadi and ISIS-Khorasan, that his activities on that day were completely harmless and not at all related to the imminent threat we believed we faced, and that Mr. Ahmadi was just as innocent a victim as were the others tragically killed,” Defense Secretary Lloyd Austin said in a statement announcing the military’s conclusions.

“We apologize,” Austin added, “and we will endeavor to learn from this horrible mistake.”

The chain of missteps ending with the missile strike came days after a suicide attack at the Kabul airport claimed the lives of at least 170 Afghans and 13 U.S. service members, prompting a sense of urgency among military officials. It also highlights flaws in the Biden administration’s strategy for targeting threats that emerge in Afghanistan from long distance, an approach analysts and critics of the president have panned as being vulnerable to inadequate intelligence and overconfidence among commanders reading ordinary behaviors as evidence of malicious intent.

The strike followed days of chaos in Kabul as thousands of Afghans tried to flee through the airport. It capped the U.S.-led war with what has come to symbolize Western intervention in Afghanistan, the Middle East and Africa: airstrikes that sometimes kill civilians, followed by initial Pentagon denials that it may have made mistakes far from public view, said Brian Castner, a senior crisis adviser at Amnesty International.

The 10 victims — three adults and seven kids — belonged to a single extended family, a neighbor who witnessed the attack said in the immediate aftermath. He described a gruesome scene of bodies “covered in blood and shrapnel” — with some of the dead children still inside the car.

“The U.S. military was only forced to admit to its failure in this strike because of the current global scrutiny on Afghanistan,” said Castner, a former Air Force bomb technician. “This is not the end of their obligations. They have to do their own internal investigation to figure out if any crimes were committed.”

Gen. Kenneth “Frank” McKenzie, who heads U.S. Central Command and had oversight of the Afghanistan mission as it came to an end last month, said Friday that officials were assessing whether anyone would be held responsible for the errant strike. The U.S. government, McKenzie added, is discussing “ex gratia” payments to compensate the victims’ families.

The commander who oversaw the operation, an American officer who has not been identified publicly, met the standard of “reasonable certainty” that a threat was imminent, according to one U.S. official, who spoke on the condition of anonymity to discuss the military’s findings ahead of Friday’s announcement.

The military’s acknowledgment comes after three news organizations, including The Washington Post, published investigations of the incident that each cast doubt on the Pentagon’s claims, including whether Ahmadi carried any explosives and whether his actions implied a man who delivered meals to displaced people was secretly moonlighting as a suicidal insurgent. McKenzie acknowledged those reports played a role in determining the military’s mistakes.

McKenzie said that leading up to the drone strike, intelligence analysts were flooded with dozens of credible reports forecasting attacks on the coalition effort to evacuate Americans and Afghans from the Kabul airport, including links to a white Toyota Corolla — which are among the most common vehicles on the city’s roads.

On the morning of Aug. 29, Ahmadi stopped near a building analysts suspected was an ISIS-K safe house, McKenzie said. He picked up and dropped off people at various places in the city, the general added, and at a few points the vehicle was loaded and unloaded with cargo.

Ahmadi arrived home a few minutes before 5 p.m. under the watchful eye of an armed Reaper drone.

The father of four had a tradition with his kids, his family later said: Ahmadi would hop out of the car and let his children finish parking. Several piled into the car, his brother said, and they reversed into the courtyard under the shade of a nearby tree.

A few minutes after Ahmadi’s arrival, the commander fired a single Hellfire missile at the vehicle, destroying the sedan in an explosion and strewing bodies through the wreckage and courtyard. The drone operator did not see any children when the missile launched, but it was already in flight when three children could be seen just as the missile struck, officials said.

Surveillance footage from the aid group Ahmadi worked for, Nutrition and Education International, and interviews with its staff provide a portrait of Ahmadi’s mundane errands against the backdrop of the city’s humanitarian crisis. His route included breakfast with colleagues, trips to a bank and police station visits to coordinate security for food distribution, along with visits to the group’s headquarters, said Steven Kwon, the group’s president.

Videos captured Ahmadi carrying containers into the compound. He filled them with water to bring home to his family because utilities in Kabul were disrupted following the Taliban’s takeover, said the group’s country director, who spoke on the condition of anonymity out of fear for his safety.

McKenzie said the heavy packages were suspected to be bundles of explosives, such as the suicide vest used at the airport attack, but upon reviewing the surveillance video and drone footage, commanders learned they had mistaken the water jugs for bombs.

Those types of canisters are common for insurgents to fill with homemade explosives because they’re inexpensive, have handles and can hold a lot of weight, and it’s possible commanders familiar with that practice were overconfident about their conclusions without considering plausible alternatives, Castner said.

A physicist who assessed imagery from the site for The Post estimated the blast’s force to be about 22 pounds of explosives at the high end — within the range of a Hellfire missile’s payload. A described secondary blast, experts said, was probably the result of fuel vapors igniting.

The investigation concurred with that assessment, McKenzie said, with the likeliest scenario being a fuel canister near the car going up in flames. The Pentagon is no longer describing that reaction as an explosion.

Whether anyone is disciplined, human rights advocates say the incident should serve as a wake-up call to the military, which has long waxed eloquent about “lessons learned” — but continues to make errant strikes that end up killing civilians.

“There is still no Department of Defense policy on civilian casualties. That’s after 20 years of fighting in Iraq and Afghanistan, and mistakes like these,” said Sarah Holewinski, Washington director for Human Rights Watch and a former senior human rights adviser at the Pentagon. “Will it be that this time lessons are learned, and U.S. policies and practices will change? Or is it going to remain the case that after the next strike the U.S. military comes out and says, ‘No, it was a perfect strike. We had all the intelligence we needed'?”

Holewinski said McKenzie’s apology, and the fact that he raised compensation for the victims, were positive signs. But she added that it was imperative for the Pentagon to make public the findings of its assessment of the strike — and any decisions about culpability — to show that officials are serious about change.

On Capitol Hill, some promised to lean on the Pentagon for answers, and conduct vigorous oversight to ensure there is full transparency and accountability. “We need to know what went wrong in the hours and minutes leading up to the strike to prevent similar tragedies in the future,” House Intelligence Committee Chairman Rep. Adam B. Schiff (D-Calif.) said in a statement.

Leading Republicans, meanwhile, refused to accept McKenzie’s statement that he is “fully responsible” for the attack, warning that the Biden administration’s posture on Afghanistan meant only more risk that such mistakes would occur in the future.

“President Biden bears ultimately responsibility,” Sen. James M. Inhofe (R-Okla.), the Armed Services Committee’s top Republican, said in a statement, adding that the president’s “precipitous withdrawal of U.S. troops from Afghanistan has left our military with an impossible mission of countering terrorists without any personnel or partners on the ground.

“The August 29 strike shows how difficult and complex counterterrorism operations can be. Unfortunately, it highlights that an ‘over-the-horizon’ strategy will only increase the complexity and difficulty. We need a more realistic strategy for keeping Americans — and Afghan civilians — safe.”

Meg Kelly, Sarah Cahlan, Dalton Bennett, Atthar Mirza and Dan Lamothe contributed to this report.