A senior military intelligence chief suggested Tuesday that Iraqi officials, perhaps working without the knowledge of Saddam Hussein (search), moved evidence of Iraq's weapons of mass destruction programs outside the country before this year's war.

James R. Clapper, who heads the National Imagery and Mapping Agency (search), described his theory as an educated hunch.

It had previously been put forward by David Kay (search), the CIA's chief weapons hunter in Iraq, as one of several possible explanations why no chemical or biological weapons, and only limited evidence of weapons programs, had been found in postwar Iraq.

Before and during the war, U.S. intelligence tracked a large number of vehicles, mostly civilian trucks, moving from Iraq into Syria, Clapper said. What was in them is unknown, although he suggested they may have contained materiel related to Iraq's weapons programs.

But some other intelligence officials have previously said they have no conclusive evidence of Iraq moving weapons to Syria or elsewhere.

Clapper also suggested that some items from Iraq's weapons programs may have been destroyed or hidden in the run-up to the war. He pointed to the discovery of buried Iraqi fighter jets as evidence that members of Saddam's government sought to hide things from invading U.S. and allied forces.

Before the war, Clapper's outfit was one of several intelligence agencies that endorsed conclusions that Iraq was working on chemical, biological and nuclear weapons. His agency analyzes satellite photos.

"We certainly feel there were indications of WMD activity," Clapper told reporters Tuesday.

But, he said, spy satellites cannot look inside buildings or trucks, so analysts often must infer what was in them based on other evidence. He said he was not surprised that actual weapons had not yet been uncovered.

The lack of discoveries in postwar Iraq has led critics to argue that the war was based on mishandled or exaggerated intelligence. The CIA and other agencies have defended their conclusions.

President Bush, in a press conference Tuesday, said Kay's discoveries so far have already justified the war. Kay reported to Congress earlier this month that he had found no prohibited weapons, but he described discoveries that he interpreted as evidence of Iraq's ambitions to restart its weapons programs.

"The American people know that Saddam Hussein was a gathering danger, as I said," Bush said. "And the world is safer as a result for us removing him from power."

Kay's search continues; his final report is expected next year.

"Saddam Hussein is a man who hid programs and weapons for years," Bush said. "He was a master at hiding things."