The former US chief weapons hunter, David Kay, called for a review of the US intelligence failure over Iraq's weapons of mass destruction but insisted political pressure was not to blame. "We were all wrong," Kay told the US Senate Armed Service Committee as he was subjected to intense questioning about his explosive disclosure that a six month search had found no evidence that Iraq had banned weapons before the US invasion in March. Kay disputed suggestions that US intelligence was warped by political pressure from the administration of President George W. Bush. "It turns out we were all wrong, probably, in my judgment. And that is most disturbing." Kay, who resigned last week as head of the Iraq Survey Group, said the investigation should continue and acknowledged "the theoretical possibility" that hidden weapons might yet be found. An "unresolvable ambiguity" about Iraq's weapons programs would probably remain, he said. "I believe that the effort that has been directed to this point has been sufficiently intense that it is highly unlikely that there were large stockpiles of deployed, militarized chemical weapons there," he said. Under questioning, Kay said no evidence was found of even small weapons stockpiles. He also did not believe large amounts of weapons were moved to Syria before the war "because there were no large stockpiles to move." Asked about trucks that Vice President Dick Cheney said last week were "conclusive evidence" that Iraq had mobile biological weapons laboratories, Kay said intelligence experts now believed these were to produce hydrogen for weather balloons. He said Iraq began rebuilding facilities at its Tuwaitha nuclear complex in 2001 but had only conducted some experiments and had not reconstituted a nuclear program. "All I can say is if you read the total body of intelligence in the last 12 to 15 years that flowed on Iraq, I quite frankly think it would be hard to come to a conclusion other than Iraq was a gathering, serious threat to the world with regard to WMD," he said. In often sharp questioning, Republicans insisted it was premature to say there were no banned weapons because the hunt has not been completed. Opposition Democrats seized upon the administration's unequivocal prewar assertions that Iraq had weapons of mass destruction. "Many of us feel that the evidence so far leads only to one conclusion," said Senator Ted Kennedy. "That what has happened was more than a failure of intelligence, it was the result of manipulation of the intelligence to justify a decision to go to war." Senator Carl Levin, the committee's ranking Democrat, complained that the Republicans were blocking an inquiry into how the administration used the intelligence to make its case for war. Kay told the senators his aim was "not political and certainly not a witch-hunt of individuals." He said the argument that US intelligence was pressured to reach a conclusion that suited the political aims was "a wrong explanation." During the weapons hunt in Iraq, he said, "I had innumerable analysts that came to me in apology that the world we were finding was not the world that they thought had existed." "Not in a single case was the explanation I was pressured to do this," he said. "The fact that it wasn't (political pressure) tells me we have a much more fundamental problem of understanding what went wrong. And we've got to figure out what was there," he said. He indicated that an over-reliance on high tech surveillance and foreign intelligence, and a lack of US spies in Iraq blinded US intelligence to what was occurring after 1998 as conditions worsened in Iraq. Intelligence analysts were under tremendous pressure to reach conclusions based on too little data, he said.