|There has been fierce fighting in Ramadi (file)|
The raid resulted in no US casualties.
"It was reported that one of the insurgents was wounded and other insurgents came to remove him from the scene," the US military statement said.
Captain Frank Pasqual, a spokesman for US central command, told Al Jazeera: "What we're looking at is a terrible case of insurgents planting bombs and using civilians as shields which resulted in an ambush and terrible tragedy."
Lieutenant-Colonel Bryan Salas, a US marine spokesman, said: "Efforts are under way to co-ordinate and offer available assistance to surviving family members.
"The concern is loss of innocent life."
Ramadi is in Anbar province, scene of some of the fiercest fighting between US forces and fighters.
Source: Al Jazeera and agencies