CIA director George Tenet has defended the gathering of intelligence later used to justify declaring war on Iraq.
Tenet: The jury is still out on many intelligence issues
No-one told security officials what to say or how to say it, he said, adding: "We always call it as we see it."
He said the intelligence services had never said Saddam Hussein was an "imminent threat" but stood by warnings about the future danger he could pose.
The search had to go on in Iraq for the weapons of mass destruction that US intelligence believed existed, he said.
Mr Tenet said he supported the establishment of the president's commission into intelligence-gathering, which is being touted as a broad review but is seen in many quarters as an inquiry into the apparent failures to identify Saddam Hussein's arsenal accurately.
The review comes after former US chief weapons inspector, David Kay, told Congress they were unlikely to find chemical and biological weapons stockpiles in Iraq and backed an inquiry into alleged failures of the intelligence agencies.
Mr Kay has called for an independent commission to examine whether politicians misused intelligence data in making the case for war.
The BBC's Adam Brookes in Washington said Mr Tenet's address amounted to him drawing the battle lines ahead of the investigation.
But US Defence Secretary Donald Rumsfeld said he did not believe there was a discrepancy between the views of Mr Tenet and Mr Kay.
Playing down any differences that might exist, he said: "The question is: is the glass half full or half empty?", a reference to the fact that both men agree the weapons hunt is not over, although Mr Kay believes it is 85% complete.
The BBC's Nick Childs said Mr Rumsfeld's apparent defiance contrasts to some of his colleagues who seem to have modified their views recently.
Mr Tenet told an audience at Georgetown University that he recognised that the key question was had the Central Intelligence Agency and others got it right or wrong when they said Saddam Hussein had or was seeking weapons of mass destruction in the key National Intelligence Estimate of October 2002.
But he said that question could not be answered. "In the intelligence business, you are almost never completely right or completely wrong," he said. "When the facts on Iraq are all in, we will be neither completely right nor completely wrong."
He added that even after reviewing operations and finding some errors, he did not believe that there could have been any other conclusions than the ones of October 2002 which highlighted the dangers.
Mr Tenet said it was important that analysts be allowed to offer their judgements without fear of political retribution.
He rejected any suggestion that the Iraq intelligence had been packaged or presented in any way to push any particular policy, though he said officials were examining whether policymakers were made sufficiently aware of gaps in knowledge.
Mr Tenet said President Bush never asked for anything but honest opinions in their daily meetings.
"He has told me firmly and directly that he's wanted [the intelligence] straight and he's wanted it honest, and he's never wanted the facts shaded."
He urged people and politicians to allow more time for the search for evidence of banned weapons in Iraq and challenged the verdict of Mr Kay that most of the work had been done.
But Mr Tenet said he was able to offer some "provisional bottom lines" on key areas:
- Missiles: "We were generally on target."
- Unmanned aerial vehicles: "We detected development of prohibited and undeclared unmanned aerial vehicles, but the jury is still out on whether Iraq intended to use its newer, smaller unmanned aerial vehicle to deliver biological weapons."
- Nuclear weapons: "Saddam did not have a nuclear weapon; he still wanted one; and Iraq intended to reconstitute a nuclear programme at some point. But we have not yet found clear evidence that the dual-use items Iraq sought were for nuclear
reconstitution. We do not yet know if any reconstitution efforts had begun, but we may have overestimated the progress Saddam was making."
- Biological weapons: "Iraq intended to develop biological weapons."
- Chemical weapons: "Saddam had the intent and capability to quickly convert civilian industry to chemical weapons production. However, we have not yet found the weapons we expected."
Mr Tenet also used his speech to mention CIA successes elsewhere in the world where he said US spies had been heavily involved in the capture of alleged terrorist masterminds connected to the 11 September 2001 and Bali attacks.
He also said US and British intelligence had been critical in understanding Libya's weapons of mass destruction programmes which the country has now abandoned.