In defending his beleaguered agency, Tenet also sounded a cautionary note.

"By definition, intelligence deals with the unclear, the unknown, the deliberately hidden," said Tenet. "When the facts of Iraq are all in, we will neither be completely right nor completely wrong."

In an interview Thursday, Kay said he remains convinced that Iraq had no stockpiles of weapons of mass destruction before the war and pointed to the detailed speech delivered a year ago to the United Nations by Secretary of State Colin Powell.

"If anyone had asked Secretary Powell that day, 'Do you think nine months after the end of the war you will still be looking for those large stockpiles?' I seriously doubt that Secretary Powell would have said, 'Yeah, it may take two years to find them,"' Kay said. "That shows to me there was something wrong in the estimate."