US marines killed several Iraqi civilians when a bus drove through a checkpoint in Ramadi, the US military.
Iraqi police said seven people died, while the US claimed three people had been killed.
In a statement the US military said: "The driver ignored verbal warning and several warning shots.
"As US Marines in vicinity of the checkpoint attempted to disable the van, the van accelerated toward the Marines. The Marines then fired upon the vehicle to protect themselves and the integrity of the checkpoint."
Ramadi police chief Brigadier Jasim al-Dulaimi said seven died in the shooting near the central governorate building where US troops are positioned.
Reuters Television footage showed the bus peppered with bullet holes. Some of the windows were shattered and others spattered with blood.