The US military has struggled to improve the cultural sensitivity of its troops — often raw youths on their first trip abroad — since the start of the occupation when the first soldiers to hit Baghdad slipped a Stars and Stripes over the head of Saddam Hussein’s statue. Jittery superiors swiftly ordered them to replace it with an Iraqi flag.

Long before the Abu Ghraib scandal, there were numerous examples of brutality and insensitivity by US troops to match tales of their courage. Sometimes it was purely a lack of local knowledge: a minor riot ensued when dogs — considered unclean in the Muslim world — were used to sniff staff entering the Oil Ministry.

At other times it was the crudeness of combat troops thrown abruptly into a peacekeeping role. “I don’t know how many women I’ve seen in labour. These people s*** out kids like turds,” a National Guardsman muttered to The Times on a patrol in Baghdad.

That contempt was quickly detected by the population, which was dismayed to see US forces obsessed with their own protection and doing little to halt the breakdown of law and order.

Much of the damage was done early on. Battle-hardened troops launched house raids that horrified Iraqis, who jealously guard their privacy and the modesty of their women. Doors were kicked in. Money and valuables were reported stolen.

But little has changed. “I’m a door kicker-inner,” one young Marine blurted out in Fallujah last month, to the dismay of his superiors.

The Marines have tried to teach their men some of the language. But most US soldiers know only how to say “move on” or “slow down”. They expect Iraqis to understand their hand signals — a bunched fist meaning “stop”, a hand waved palm-down meaning “slow” — and will frequently shoot to kill if confused drivers fail to respond.

The intensifying violence has only increased the distance between US troops and ordinary Iraqis, with ever-higher walls being built around bases, and US military vehicles warning drivers they will be shot if they come close. Even the Iraqi shops on US bases have closed for fear of rebel infiltration.