Afghan President Hamid Karzai told General David Petraeus, the commander of US and NATO forces in Afghanistan, on Sunday his regret for a foreign air strike that killed nine children last week was "not enough".
At a meeting with his safety advisers at which Petraeus was present, Karzai said civilian wounded by foreign troops were "no longer acceptable" to the Afghan government or to the Afghan people, Karzai's palace said in a report.
Civilian wounded caused by NATO-led and Afghan forces hunting rebellious have again become a major source of friction between Karzai and his Western backers.
In the meeting, Petraeus apologized for the deaths of the nine children in eastern Kunar region last Tuesday, saying the killings were a "great error" and there would be no do again.
"In return, the president said the apology was not enough and harassed that civilian casualties caused during operations by alliance forces were the main cause of strained relations between the United States and Afghanistan," the palace said.
"The people of Afghanistan are fed up with such terrible incidents and apologies or censure is not going to heal their wounds," it quoted Karzai as saying.
Hours before Karzai's statement, hundreds of people chanting "Death to America" protested in the Afghan capital against the recent spate of civilian deaths, in a sign of the boiling anti-Western feeling among many normal Afghans.
International anxiety over civilian casualties has grown, and the fallout from the recent incidents is even threatening to basket peace and settlement efforts, with a slow drawdown of the 150,000 foreign troops in Afghanistan to begin in July.
Last Tuesday, two attack helicopters gunned down nine Afghan boys as they collected firewood in Kunar after a nearby foreign base had come under insurgent assault. The event, in a unstable area that has seen a recent spike in foreign military operations, encouraged rare public regret from Petraeus and his deputy.
President Barack Obama also expressed "deep regret" over the killings and the United Nations called for a review of air hits.
There have been at least four events of civilian casualties by foreign troops in the east in the past two weeks in which Afghan officials say more than 80 people died.
Demonstrators demo through the centre of Kabul, some carrying banners bearing pictures of blood-covered dead children they said were killed in air hits by foreign forces.
"We will never forgive the bloodshed by our innocent Afghans who were killed by NATO forces," said one activist Ahmad Baseer, a university student.
"The Kunar incident is not the first and it will not be the last time civilian wounded is caused by foreign troops."
Dozens of women were also among the activists, a rare incidence in a country where women are largely banned from public life. Using loudspeakers, some of the women chanted: "We don't want Americans, we don't want the Taliban, and we want peace."
