"My belief that they did not move large stockpiles of WMD to Syria is based on my conclusion that there were not large stockpiles to move," he told a Senate panel.

Some Republicans have sought to explain the US failure to find weapons of mass destruction in Iraq by suggesting that Saddam Hussein sent them across the border to Syria for safekeeping.

There was a large movement of truck and rail traffic into Syria before the war, but Kay said investigators are unlikely to find out what was in the containers barring a change in Damascus.

"Did they move small amounts? Did they move technology? Did they move documentation? It's absolutely possible; I would say probable," Kay said.

"But my personal belief is that they did not move large stockpiles. Because I do not believe they have reconstituted a capability that had produced large stockpiles," he said.

WAR.WIRE