US media say an American drone strike in the Afghan capital Kabul, targeting a local Islamic State organization, may have been a mistake.
Several civilians, including children, were killed in the attack on a vehicle in a residential area on August 29.
The US military said at the time the large explosion that occurred when the vehicle was destroyed indicates that it was carrying "a substantial amount of explosive material."
But the Washington Post on Friday quoted multiple experts as saying it is highly unlikely there was a substantial amount of explosives in the car, and that gasoline vapors may have played a role in a subsequent blast.
They say the homes and walls near the vehicle would have otherwise sustained catastrophic damage from the blast wave, and pointed out that the vehicle's headlight remained turned on immediately after the air strike.
The New York Times says the driver was a longtime worker for a US aid group, and quoted his family members as saying he was applying for a visa to immigrate to the United States and had no reason to attack US forces.
The air strike was carried out at a time when US ground troops were withdrawing from Afghanistan.
Several experts have pointed to the difficulty of taking measures against terror attacks at a time when information gathering capabilities were diminishing.