Hours after an American military drone strike in Kabul on Sunday, US defence department officials said it had blown up a vehicle laden with explosives, eliminating a threat to Kabul’s airport from the Islamic State Khorasan group.

But at a family home in Kabul on Monday, survivors and neighbours said the strike had killed 10 people, including seven children, an aid worker for an American charity organisation and a contractor with the US military.

On Monday, US anti-missile defences intercepted rockets fired at Kabul’s airport. A US official said initial reports did not indicate any US casualties from as many as five missiles fired on the airport. The Islamic State claimed responsibility for the rocket attacks.

On Sunday evening, Zemari Ahmadi, who worked for the charity organisation Nutrition and Education International, was on his way home from work after dropping off colleagues, according to relatives and colleagues interviewed in Kabul.

As he pulled into the narrow street where he lived with his three brothers and their families, the children, seeing his white Toyota Corolla, ran outside to greet him. Some clambered aboard in the street, others gathered around as he pulled the car into the courtyard of their home.

It was then that they say the drone struck.

The missile hit the rear end of the Corolla in the narrow courtyard inside the walled family compound, blowing out doors, shattering windows and spraying shrapnel. Ahmadi and some of the children were killed inside his car; others were fatally wounded in adjacent rooms, family members said.

An Afghan official confirmed that three of the dead children were transferred by ambulance from the home on Sunday.

Ahmadi’s daughter Samia, 21, was inside when she was struck by the blast wave. “At first I thought it was the Taliban,” she said. “But the Americans themselves did it.”

Samia said she staggered outside, choking, and saw the bodies of her siblings and relatives. “I saw the whole scene,” she said. “There were burnt pieces of flesh everywhere.”

Among the dead was her fiancé, Ahmad Naser, 30, a former army officer and contractor with the US military who had come from Herat, in western Afghanistan, in the hopes of being evacuated from Kabul.

A spokesman for the US Central Command said on Sunday that the US military had carried out a drone strike against an IS-K vehicle planning to attack Hamid Karzai International Airport. The group had claimed responsibility for the suicide bombing at the airport on Thursday.

On Monday, Capt. Bill Urban, the spokesman, reaffirmed an earlier statement that the military hit a valid target, an explosives-laden vehicle. He also repeated that the military was investigating claims of civilian casualties.

Ahmadi was a technical engineer for the local office of Nutrition and Education International, an American nonprofit based in Pasadena, California. His neighbours and relatives insisted that the engineer and his family members, many of whom had worked for the Afghan security forces, had no connection to any terrorist group.