"It was a successful operation. [Abu Ghadiyah] is believed to be dead. This undoubtedly will have a debilitating effect on this foreign fighter smuggling network," the official said.
A second official told the agency that only people the forces considered a threat had been targeted and that women and children were alive when the team left.
A US intelligence official told Associated Press news agency there was information that Abu Ghadiyah was about to carry out an attack in Iraq and that this had led to the raid.
"The trip wire was knowing an attack was imminent, and also being able to pinpoint his location," the official said.
The official said the US had similar but less detailed information in the spring
Shortly afterwards, 11 Iraqi policeman were killed in an attack the US believes was led by Abu Ghadiyah personally.
Sunday's attack took place during the afternoon rest period, with a troop assault preferred over a missile strike to reduce civilian casualties, the intelligence official said.
Syria says the raid was US "terrorist aggression"
The US had repeatedly asked Syria to hand over Abu Ghadiyah but Damascus said it was monitoring his activities, another US military official told AP.
Newly released amateur footage said to show the raid shows villagers pointing to the sky as helicopters fly in.
The mobile phone video does not show any landings but has images purportedly from after the attack, showing a crowd looking at blood-stained bodies. The authenticity of the video has not been verified.
Syria says all the victims were civilian.
Foreign Minister Walid Muallem said they were a father and his three children, a farm guard and his wife, and a fisherman.
He said: "Killing civilians in international law means a terrorist aggression. We consider this criminal and terrorist action."
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