Among the damage found by Mr Curtis, who was invited to Babylon by Iraqi antiquities experts, were cracks and gaps where somebody had tried to gouge out the decorated bricks forming the famous dragons of the Ishtar Gate.
He saw a 2,600-year-old brick pavement crushed by military vehicles, archaeological fragments scattered across the site, and trenches driven into ancient deposits.
Vast amounts of sand and earth, visibly mixed with archaeological fragments, were gouged from the site to fill thousands of sandbags and metal mesh baskets. When this practice was stopped, large quantities of sand and earth were brought in from elsewhere, contaminating the site for future generations of archaeologists.
In his report, Mr Curtis accepted that initially the US military presence helped protect the site from looters. But he described as "regrettable" the decision to set up a base in such an important spot.
He found that large areas of the site had been covered in gravel brought in from outside, compacted and sometimes chemically treated to provide helipads, car parks and accommodation and storage areas. "The status of future information about these areas will therefore be seriously compromised," he said.