PORT-AU-PRINCE: The US paratrooper had a simple message for the people of Haiti. Dressed in khaki, carrying an assault rifle and with the iconic sight

of Black Hawk helicopters taking off behind him, he said: “I don’t plan on firing a single shot while I’m here. I’ve been in Iraq three times and I’ve done enough of that.” The paratrooper was part of the 82nd airborne division from Fort Bragg, North Carolina. This time, though, the troopers and their commanding officers — right up to the rank of commander-in-chief, Barack Obama — were keen as mustard to present themselves as helpers and carers, not warriors.

The order has come down from on high that when out patrolling the stricken streets of the city of Port-au-Prince, the paratroopers should have their rifles slung behind their backs. None of that strong-arm brandishing of metal that epitomised the early days in Iraq. “We’ve been told not to draw attention to our guns,” the paratrooper, Sgt David Gurba, said.

By Monday, the US military was visibly out in force at the main airport in Port-au-Prince. Two mammoth C17 military transport aircraft were on the tarmac, one of which landed in front of us, the other unloading jeeps and armoured vehicles. Providing a solid background hum, the Black Hawks moved in and out of the airport every five minutes, swinging round from the airport to the USS Carl Vinson where 30 of the helicopters were based.

There are 1,700 US troops here, substantially less than the 5,000 or so that had been promised by now. But in the next couple of days 2,200 reinforcements from the 22nd Marine Expeditionary Unit, backed up by amphibious units, are scheduled to arrive.

By mid-week, the US military says, it will have up to 5,000 personnel on the ground and a similar number at sea.

You can’t move such numbers of US soldiers into a sovereign country without it looking, slightly inevitably, like an invasion. But that’s an impression the Americans are hyper-sensitive about countering.

“I cannot say this more clearly,” the spokesman for the commander of the joint task force told us, standing on the tarmac in his military fatigues. “The focus of the American presence on the ground is to help with the humanitarian work.”

Over at the US embassy on the outskirts of the city, the same message was delivered even more directly: “This is a primary concern of ours,” the embassy spokesman told us. “We want the people of Haiti to understand that we are here to help. We are not here to invade or occupy.” The desire to avoid any semblance of invasion is understandable, given the past few years in Afghanistan and Iraq.

But there’s also a local sensitivity, born of wave upon wave of American interference in the internal affairs of Haiti.

The Haitian in whose house in Port-au-Prince we are staying keeps a cherished machete on his wall. It was used, he explained to me one night, by his grandfather to attack US soldiers during the 1915-1934 American occupation of his country.