When Ezmarai Ahmadi returned home from work on Sunday evening in Kabul, the usual gaggle of squealing children were waiting to greet him -- his sons and daughters, and a slew of nieces and nephews.

He pulled his white sedan into the driveway of a modest house in Kwaja Burga, a densely populated neighbourhood in the northwest of the Afghan capital, and handed the keys to his eldest son to park.

Youngsters piled into the vehicle -- pretending the parking routine was an adventure -- while Ezmarai watched from the side.

Then out of the blue Afghan sky, a missile came screeching down -- striking the car with a terrible force and obliterating the lives of 10 people in an instant.

The United States said Sunday it had destroyed an explosive-laden vehicle in an airstrike, thwarting a bid by the Islamic State to detonate a car bomb at Kabul airport.

On Monday, it looked as if they could have made a terrible mistake.

"The rocket came and hit the car full of kids inside our house," said Aimal Ahmadi, Ezmarai's brother. "It killed all of them."

Aimal said 10 members of the family died in the airstrike -- including his own daughter and five other children.

Ezmarai Ahmadi, 36, died alongside his three sons and nieces and nephews.

On Monday, when AFP visited the scene, Aimal was impatiently waiting for other relatives to arrive to help him organise burials for most of his family.

"My brother and his four children were killed. I lost my small daughter... nephews and nieces," he said disconsolately. "We are aware of reports of civilian casualties following our strike on a vehicle in Kabul," Captain Bill Urban, a US military spokesman, said in a statement. 

- Despair -

Aimal can scarcely believe his brother could be mistaken for an Islamic State sympathiser, let alone an operative planning a deadly car bomb attack.

Ezmarai was an engineer working with a non-governmental organisation -- an ordinary Afghan trying to make ends meet in a turbulent time.

US nerves have been frayed since an IS suicide bomber triggered a massive blast at an entrance to the airport on Thursday, as huge crowds clamoured to get inside in the hope of getting aboard one of the final evacuation flights out of Afghanistan.

Nearly 100 Afghans were killed, and also 13 US service members -- just days before the last American soldier withdrew from the country on Monday night.

Against that backdrop, US intelligence had warned of another imminent attack, and on Sunday the US military said it had stopped one before it happened.

"We are still assessing the results of this strike, which we know disrupted an imminent ISIS-K threat to the airport," Urban said Sunday, using an acronym for the Afghan branch of the Islamic State group.

"We know that there were substantial and powerful subsequent explosions resulting from the destruction of the vehicle, indicating a large amount of explosive material inside that may have caused additional casualties," he continued.

"It is unclear what may have happened, and we are investigating further."

The deaths were among the last reported before the final US forces flew out of Afghanistan on Tuesday, after a brutal 20-year war.

Just over 38,000 civilians were killed between 2009 and the end of 2020, according to the United Nations Assistance Mission in Afghanistan, which began systematically recording civilian casualties in 2009.

More than 70,000 others were wounded over the same period.

When locals heard the blast in the neighbourhood, they swiftly came to see what help they could offer.

"All the children were killed inside the car, the adults were killed just outside. The car was on fire -- we could hardly find body parts," said one, named Sabir.

"We would be deeply saddened by any potential loss of innocent life," the US spokesman said in the statement.

But those words rang hollow for another neighbour, Rashid Noori.

"The Taliban kill us, IS kill us and the Americans kill us," he said.

"Do they all think our children are terrorists?"