WASHINGTON — In a scathing report, a presidential commission said today that America's spy agencies were "dead wrong" in most of their judgments about Iraq's weapons of mass destruction before the war and that the United States knows "disturbingly little" about nuclear threats posed by many of its most dangerous adversaries.

The commission called for dramatic change to prevent future failures. It outlined 74 recommendations and said that President Bush could implement most of them without action by Congress. It urged Bush to give broader powers to John Negroponte, his choice to be the new director of national intelligence, to deal with any challenges to his authority from the CIA, Defense Department or other elements of the nation's 15 spy agencies.

It also called for sweeping changes at the FBI to combine the bureau's counterterrorism and counterintelligence resources into a new office.

The report was the latest tabulation of intelligence shortfalls documented in a series of investigations since the terror attacks of Sept. 11, 2001 against the United States. Numerous investigations have concluded that spy agencies had serious intelligence failures before the attacks. Today's report concluded that the problem still has not been fixed, three years after al-Qaida struck America.

"The flaws we found in the intelligence community's Iraq performance are still all too common," it said.

Bush received the report in a meeting with commission members in the Cabinet Room where he was flanked by the panel's co-chairmen, Republican Laurence Silberman, a retired federal appeals court judge, and Democrat Charles Robb, a former senator from Virginia. Bush did not comment but his spokesman said the president would set up a process to review each recommendation and act "in a fairly quick period of time."

The report does not accuse the administration of manipulating the intelligence. The commission noted that it wasn't authorized to investigate how policy-makers used this information.

"The daily intelligence briefings given to you before the Iraq war were flawed," it said. "Through attention-grabbing headlines and repetition of questionable data, these briefings overstated the case that Iraq was rebuilding its WMD programs."

In an implicit swipe at the Bush administration, Senate Minority Leader Harry Reid, D-Nev., said the report did not review how federal policymakers used the intelligence they were given.

"I believe it is essential that we hold both the intelligence agencies and senior policymakers accountable for their actions," Reid said.

Bush signed on to the idea of an independent investigation only belatedly. The White House had said it wanted to give the weapons search in Iraq more time. But pressure grew from Republicans and Democrats alike after the former chief U.S. weapons inspector in Iraq, David Kay, resigned saying the pre-war estimates of weapons in Iraq, which Bush used to justify war there, "were almost all wrong."

Even then, the White House insisted the commission's mandate be broaded to other nations, prompting criticism that the panel might be too overloaded to thoroughly examine its original subject, Iraq.

The unclassified version does not go into significant detail on the intelligence community's assessment of countries such as Iran, North Korea, China and Russia because commissioners did not want to tip the U.S. hand about what is known. Those details are included in the classified version.

"Across the board, the intelligence community knows disturbingly little about the nuclear programs of many of the world's most dangerous actors," the report said. "In some cases it knows less now than it did five or 10 years ago."

Rep. Ike Skelton of Missouri, the top Democrat on the House Armed Services Committee, said the failures were widespread.

"I don't think you can blame any one person, although the buck does stop at the top of every one of these agencies," Skelton said. "But quite honestly, the fault is spread out across all the agencies."

The commission was formed by Bush a year ago to look at why U.S. spy agencies mistakenly concluded that Iraq had stockpiles of weapons of mass destruction, one of the administration's main justifications for invading in March 2003.

"We conclude that the intelligence community was dead wrong in almost all of its prewar judgments about Iraq's weapons of mass destruction," the report said. "This was a major intelligence failure."

The main cause was the intelligence community's "inability to collect good information about Iraq's WMD programs, it said, and serious errors in analyzing what information it could gather and a failure to make clear just how much of its analysis was based on assumptions rather than good evidence.

"On a matter of this importance, we simply cannot afford failures of this magnitude," the report said.

On al-Qaida, the commission found that the intelligence community was surprised by the terrorist network's advances in biological weapons, particularly a virulent strain of a disease that the report keeps secret, identifying it only as "Agent X."