NATO has apologized following a coalition probe that found that nine Afghan civilians were killed during operations in eastern Afghanistan on Tuesday.
In a statement Wednesday, NATO said preliminary findings show that coalition forces mistakenly fired on the civilians while responding to an insurgent attack in the Darah-Ye Pech district of Kunar province.
Afghan officials had said nine children collecting firewood were killed in the NATO airstrike.
The coalition probe said there was miscommunication about exact location of the insurgents.
The commander of U.S. and NATO forces in Afghanistan, General David Petraeus, expressed deep regret for the tragedy and said he will personally apologize to President Hamid Karzai when the Afghan leader returns from London this week.
Earlier Wednesday, President Karzai condemned the civilian casualties and criticized NATO forces, saying troops should focus on terrorist sanctuaries. He warned the coalition could face "huge problems" if the inadvertent killing of civilians does not stop.
Petraeus said the incident was "particularly distressing" given that he had recently directed commanders to review a "tactical directive that is intended to reduce civilian casualties to the absolute minimum."
General Petraeus also said he has ordered coalition leaders and helicopter crews to be briefed once again on the directive "to protect the lives of innocent Afghans."
A recent Afghan investigation found that as many as 64 civilians were killed during separate NATO operations in Kunar province late last month. The coalition says it is investigating the allegations.
On Wednesday, dozens of villagers took to the streets in Kunar to protest the latest incident.
Mr. Karzai met Tuesday in London with British Prime Minister David Cameron, who pledged long-term support for Afghanistan as international troops prepare to begin transferring security responsibility to Afghan forces.