United States forces in Afghanistan are to review an inquiry into an air raid last month after new video images indicated scores of civilian deaths.
The US earlier said no more than seven civilians died in the attack on the western province of Herat.
However, the Afghan government and the United Nations said up to 90 people were killed, including many women and children.
The US general in charge of Nato-led troops in Afghanistan said at the weekend that he was requesting the US military's Central Command to review the investigation into the air raid in August.
General McKiernan said ISAF realised there was "a large discrepancy between the number of civilian casualties reported by US and Afghan National Army soldiers, and local people".
Video footage - apparently of the aftermath of the raid - has been seen by top military figures and diplomats in Kabul.
The BBC reports it shows some 40 dead bodies lined up under sheets and blankets inside a mosque. The majority of the dead are children.
The crying of relatives and the survivors of the bombing raid is Clearly heard on the tape.
US forces had originally said seven civilians were killed in a "successful" US raid targeting a Taliban commander in Azizabad village in the Shindand district of Herat.