Kabul, Afghanistan (CNN) -- A coalition commander offered his alliance's "sincere apologies" Sunday for an airstrike that he said killed nine civilians in southern Afghanistan.
Maj. Gen. John Toolan, the head of the International Security Assistance Force's command in southwest Afghanistan, said his apology was being made "on behalf of the coalition" and its top leaders, including U.S. Army Gen. David Petraeus. He pleaded with Afghans to not only forgive, but also to work with coalition forces in hopes of bolstering their security.
"I offer our heartfelt apologies to the families and friends of those killed," Toolan said in a statement. "I ask that the Afghan people continue to trust and assist their security forces, so that together we can stop the senseless killing brought upon us by an enemy who wants to exploit the Afghan people through fear and violence."
Earlier, Afghan and NATO officials said that Saturday's attack in Helmand province killed a dozen children and two women. There was no immediate explanation for the disparity between this figure and the toll of nine civilians killed offered Sunday by Toolan, who also noted that a U.S. Marine was killed immediately before the strike.
The strike provoked the ire of Afghan President Hamid Karzai, who strongly condemned the airstrike and insisted he was warning the U.S military and government "for the last time" on behalf of the Afghan people about civilian deaths. He called the operation a mistake, but offered a different death toll, saying 10 children, two women and two men were killed.
According to Toolan's statement, the strike occurred after coalition troops came under attack in Helmand's Now Zad district, leading to the death of the American Marine.
Five insurgents then moved into a compound, where they continued to fire, the ISAF commander said. An airstrike was then ordered on this building "to neutralize the threat."
Residents claimed that projectiles coming from a coalition helicopter hit two houses where women and children were staying, ISAF spokesman Daud Ahamadi had said earlier.
"Unfortunately, the compound the insurgents purposefully occupied was later discovered to house innocent civilians," Toolan said in his statement..
Even as a full investigation into the incident continues, the ISAF commander said, "We will ensure we make amends to the families (of those killed) in accordance with Afghan culture."
Helmand province, a Taliban stronghold that borders Pakistan, has been the scene of intense fighting this month since insurgents launched their so-called spring offensive.
Anger in Afghanistan and Pakistan over civilian casualties has mounted in recent months following NATO airstrikes that have killed dozens along their shared border.
In March, U.S. Defense Secretary Robert Gates offered a personal apology to Afghan President Karzai for the killings of nine boys in a helicopter attack targeting insurgents.
The top coalition commander in Afghanistan has warned of a likely increase in high-profile attacks by insurgents looking to demonstrate their ability to strike. In a letter this month to ISAF forces, Petraeus said the attacks may increase the risk of civilian casualties and put Afghan and ISAF forces in difficult situations.
CNN's Larry Shaughnessy contributed to this story.