The NATO-led International Security Assistance Force (ISAF) carried over an air strike on two civilian houses, killing seven boys, five girls and two women. NATO officials said that the air raid was conducted to capture five insurgents, who killed a US Marine.
The joint statement issued by Gen David Petraeus, Lt Gen David Rodriguez and Marine Maj Gen John Toolan said that top priority was to prevent civilian casualties and it took such cases very seriously.
Earlier, Afghan President Hamid Karzai condemned the deaths caused by NATO air strikes. He called the air strike as a "great mistake" and gave his "last warning to the US troops and US officials in this regard."
"The president called this incident a great mistake and the murdering of Afghanistan's children and women, and on behalf of the Afghan people gives his last warning to the US troops and US officials in this regard," statement released by Karzai's office said.
ISAF official said that they had assigned a team to find out the issues behind the air strike in Helmand province.
The fresh attack on civilians in Afghanistan happened amidst surging protest against foreign troops. Similarly, few days back NATO troops' air strike at night had killed four people, including two women.