NATO says it is looking into whether its forces killed or wounded up to seven Afghan civilians during operations in southern Helmand province.
In a statement Thursday, the alliance said its troops came under heavy fire in the Lashkar Gah district and that air strikes were called in to provide support.
NATO said the wounded were immediately evacuated to a medical facility for treatment.
In eastern Paktia province Thursday, NATO says Afghan and coalition forces killed more than 20 insurgents during an operation aimed at disrupting the Haqqani network, which has close ties to al-Qaida.
In other violence, NATO says its forces mistakenly killed an Afghan woman during a clash late Wednesday with insurgents in the Musa Qala district of Helmand.
NATO expressed deep regret and said it must continue its emphasis on reducing the loss of civilian life to an absolute minimum.
In central Wardak province Thursday, several hundred Afghans blocked a main road and shouted "Death to America" to protest the alleged killing of three civilians during a NATO raid in the Sayed Abad district overnight.
NATO says Afghan and international forces targeted a series of compounds in search of a Taliban commander and killed several suspected insurgents who showed what it said was "hostile intent."
Meanwhile, a Christian aid organization says it believes a group of non-local fighters killed 10 members of its medical team in an ambush last week.
The International Assistance Mission said Thursday its own probe suggests the killings in Badakhshan province were not the result of a robbery.
Also Thursday, Danish Prime Minister Lars Loekke Rasmussen, on a visit to Britain, said his country hopes to withdraw its combat troops from Afghanistan by 2015.
Some information for this report was provided by AFP.