The Pentagon has released an aerial photograph taken two days before the Iraq invasion showing two trucks at the site where 377 tons of high explosives went missing.
President Bush and Pentagon officials have argued Saddam Hussein's government may have moved the material before the start of the war in order to protect it from US attack.
But ABC news last night showed footage that appeared to confirm that explosives did not disappear until after the United States had taken control of the facility.
The Pentagon image depicted a small part of the sprawling Al Qaqaa arms site near Baghdad, taken on March 17th 2003, showed a large tractor-trailer carrying white containers and a smaller truck parked behind it.
The image was declassified just days before the US presidential election as President George W. Bush faces charges by Democratic challenger Mr John Kerry that the administration committed a blunder by failing to safeguard the powerful explosives.
The missing explosives had been monitored by inspectors from the Vienna-based International Atomic Energy Agency until days before the released photograph was taken.
ABC News last night said experts believe barrels shown in its footage contain the high explosive HMX. The video was shot by an affiliate TV station embedded with the US Army's 101st Airborne Division when troops passed through the storage facility on April 18th, 2003, nine days after the fall of Baghdad.
ABC's experts say UN markings are clear on the sealed containers.
"I talked to a former inspector who's a colleague of mine. He confirms that, indeed, these pictures look just like what he remembers seeing inside those bunkers," Mr David Albright, a former UN weapons inspector in Iraq, told the network.
ABC said the barrels seen in the video were found inside locked bunkers that had been sealed by inspectors from the UN's International Atomic Energy Agency just before the war began.
"The seal's critical. The fact that there's a photo of what looks like an IAEA seal means that what's behind those doors is HMX," Mr Albright said.
Defence Secretary Mr Donald Rumsfeld has argued the explosives may have been gone by the time US forces got there. "People who use hair-trigger judgment to come to conclusions about things that are fast-moving frequently make mistakes that are awkward and embarrassing," he said.