The U.S. military said reports that more than 100 civilians died in fighting earlier this week in western Afghanistan are "grossly exaggerated."
But U.S. media said American officials are acknowledging that U.S. airstrikes in western Farah province did kill some civilians. The New York Times and CNN did not identify the officials.
Officials said findings from a joint U.S.-Afghan investigation into the civilian deaths could be released as early as Friday.
Local Afghan officials have said the U.S. airstrikes and related fighting on Monday and Tuesday killed more than 100 people, and possibly as many as 147.
Meanwhile, NATO officials in Afghanistan said two British soldiers were killed in a suicide attack late Thursday that also left at least 16 civilians dead.
Afghan authorities originally said at least 12 civilians were killed in the attack in southern Helmand province. At least 22 people were injured.
The civilian deaths in western Afghanistan this week sparked protests by local residents. Dozens of protesters clashed with police Thursday in Farah's main city during a demonstration.
U.S. Defense Secretary Robert Gates expressed regret at the casualties allegedly caused by the airstrikes.
Amnesty International emphasized the need for a transparent investigation. It released a statement Thursday saying if the figures are verified, the civilian death toll from the attack in Farah will be one of the highest since the Taliban was ousted in 2001.
Some information for this report was provided by AFP, AP and Reuters.