US military raid on a house near Afghanistan's border with Pakistan became a new source of tension on Thursday, with the Americans calling it a successful counter-terrorism strike and the Afghans saying it left three innocent civilians dead and two wounded, including a 4-year-old boy bitten by an attack dog. The raid took place on Wednesday in the village of Kundi, in Khost Province. American military leaders and Afghan officials said they were investigating the conflicting accounts of what happened. But President Hamid Karzai, who has grown increasingly impatient with the American-led war effort against the Taliban insurgency, condemned the raid in front of government leaders and foreign diplomats, saying that "entering by force to our people's houses is against the government of Afghanistan." Mr. Karzai, who will face an election next year, is under enormous pressure from Afghans who say the seven-year-old war against the Taliban has devastated the country and led to many civilian casualties at the hands of American-led forces. The raid took place on the same day that diplomats in Kabul called on foreign forces to increase their sensitivity to win over Afghans. In Khost, American-led forces blasted the gate of the house early on Wednesday, then fatally shot the family's father and mother and a male relative, according to Tahir Khan Sabry, deputy governor of the province. Their relationship with the wounded boy was unclear, and another woman was also bitten. Mr. Sabry described all the victims as noncombatant civilians. The American military said that the raid led to the detention of an operative of Al Qaeda and that those killed were armed and showing "hostile intent." Grenades, AK-47s, pistols and a shotgun were confiscated, American officials said. The dispute over the Khost raid coincided with a visit to Afghanistan by Senator John Kerry, Democrat of Massachusetts, who said the United States needed to win local support for the war. In recent months, the governor of Khost, Arsala Jamal, has frequently complained about the actions of United States Special Forces here. He said episodes that harmed civilians undermined the progress of reconstruction efforts. In Khost, public outrage over the house raid was visible at the funerals for those who were killed. The use of dogs in military actions is especially delicate for Afghans after the release of images showing dogs being used to intimidate detainees at the Bagram prison in Afghanistan and Abu Ghraib prison in Iraq. "I saw the 4-year-old boy, and he had an injury under his knee that was definitely the mark of a dog bite," said Rasoul Adel, a local television reporter.