President George W Bush has welcomed a study that says US intelligence agencies know "disturbingly little" about enemy weapons programmes.
The CIA's problems have been highlighted in a number of reports
Describing the report as "extremely significant", he said US intelligence needed "fundamental change" to face the threats of the 21st Century.
The study makes recommendations for new director of US intelligence John Negroponte, who heads 15 spy agencies.
The study in particular criticises US collection of intelligence in Iraq.
The report says dramatic changes are needed to prevent failures similar to the fiasco over Iraq's missing weapons, including the creation of a a national counter-proliferation centre to combat the spread of weapons of mass destruction.
Intelligence 'dead wrong'
Mr Bush said intelligence had to be "timely and accurate".
"We need to adjust to the threats and adjust our capabilities to meet those threats," he said.
"The cost of underestimating a threat could be tens of thousands of lives."
Several independent inquiries have already examined the role that intelligence played in the run-up to the US-led invasion of Iraq in 2003.
But the current commission, led by Judge Laurence Silberman and former Senator Charles Robb, is the only inquiry ordered directly by President Bush.
"The intelligence community was dead wrong in almost all of its pre-war judgments about Iraq's weapons of mass destruction," the panel concluded.
"We simply cannot afford failures of this magnitude," it added.
Looking beyond Iraq, the report said: "The bad news is that we still know disturbingly little about the weapons programs and even less about the intentions of many of our most dangerous adversaries."
In response White House spokesman Scott McClellan said the administration would "act on those recommendations in a fairly quick period of time".
The commission did not name any country in the declassified version of the report - but analysts say the statement refers to such countries as North Korea and Iran.
Iran's nuclear programme - which Tehran says is peaceful - has sparked international concerns.
The panellists have more than 70 recommendations for Negroponte
North Korea has pulled out of the nuclear Non-Proliferation Treaty and says it has nuclear weapons.
New CIA chief Porter Goss reportedly sent an e-mail to staff last week in an effort to boost morale ahead of the commission's findings.
Previous inquiries into US intelligence capabilities, including the 9/11 Commission, led to widespread reform of the intelligence services, including the creation of the new post of director of national intelligence.
President Bush chose Mr Negroponte, an experienced diplomat, for the role, but the appointee has yet to take up his position.
In addition, long-serving CIA chief George Tenet stepped down. Mr Goss took up the post promising large-scale internal reform.