A small number of visitors have recently visited the Mesopotamian site to analyse the damage on the 2,000-year-old city, which has recently been made a UN World Heritage Site.
McGuire Gibson, an archaeology professor at the University of Chicago who has visited the site, said the air war carried out by the coalition forces had caused significant damage.
Gibson was also on a UN team that investigated stolen or damaged Iraqi antiquities after the war. 'Probably the worst damage was caused by the exploding of munitions by US forces,' he said.
He added that the military eventually 'diminished' the blasts, which were threatening to destabilise buildings in Hatra, but continued detonating explosives in the area.
After the US-led invasion in 2003, looters shot and damaged decorated features on Hatra's walls. Some relics and statues were rescued after they were rushed away to museums in Baghdad and Mosul during the conflict.
Other damage at the site is clear, the archaeologist added. In the 1990s Iraqi leader Saddam Hussein started to reconstruct parts of the site - but ordered that bricks stamped with his name be used.