The US-led military coalition in Afghanistan says a number of civilians appear to have died in air strikes in the southern province of Helmand.
Coalition and Nato-led forces, in co-operation with Afghan troops, launched the strikes against Taleban insurgents on Friday.
Local officials say they believe tens of civilians died but there has been no independent confirmation of this.
President Hamid Karzai recently accused foreign troops of acting "recklessly".
The coalition said the latest incident had been sparked when its forces, working with the Afghan national army to clear a river valley, came under heavy insurgent fire, including the use of rocket-propelled grenades.
It said its forces had identified several rebel positions, returned fire and then called in air strikes by the coalition and the Nato-led Isaf, which destroyed all the rebel positions.
A coalition spokesman said that later the remains of people who appeared to be civilians were found and that these bodies were in the places previously defined as firing positions.
Update
Afghanistan's President Hamid Karzai has ordered a probe into the incident.