WASHINGTON - National security adviser Condoleezza Rice told the September 11 commission today that four US presidents including George W. Bush failed to fully mobilise against terrorism, but there was no "silver bullet" that could have averted the deadly attacks on America.

In highly charged testimony that has taken on enormous political importance, Rice, under oath and broadcast live to a national television audience, clashed with Democratic members of the bipartisan commission over whether the Bush administration was negligent in the summer before the hijacked airliner attacks.

"The terrorists were at war with us, but we were not yet at war with them. For more than 20 years, the terrorist threat gathered, and America's response across several administrations of both parties was insufficient," Rice said.


"Tragically, for all the language of war spoken before September 11, this country simply was not on a war footing ... There was no silver bullet that could have prevented the 9/11 attacks."

Commissioner Richard Ben-Veniste, a Democrat, was the first to take on Rice, focusing on a briefing given Bush on Aug. 6, 2001, at which a document was presented entitled "Bin Laden Determined to Attack Inside the United States."

As members of the audience, including some family members of 9/11 victims applauded, Ben-Veniste demanded the report be declassified.

Commissioner Bob Kerrey, a former US Democratic senator, revealed some of the still-classified memo.

"This is what the August 6 memo said to the president -- that the FBI indicates patterns of suspicious activity, and I'd say it's consistent with preparations for hijacking," Kerrey disclosed.

Bush called Rice, who will return to testify before the panel in private, from his pickup truck on his Texas ranch after the three-hour hearing to congratulate her. But some family members of victims of the attacks expressed anger.

"No one wants to take any responsibility. Three thousand people died and all they want to talk about is structural problems. They should be ashamed of themselves," said Bob McIlvaine, whose son died when the World Trade Center towers were destroyed in New York.

Rice's testimony came in the midst of a bitter presidential campaign and in a week that has seen heavy and widespread fighting in Iraq.

Bush had opposed creation of the commission and resisted calls for public testimony by Rice until public and political pressure grew too strong.


Rice responded to damaging testimony by former White House counterterrorism chief Richard Clarke, who told the panel Bush ignored warnings about al Qaeda before the attacks and focused mistakenly on Iraq afterward.

She sharply denied Clarke's assertion that Bush pushed him to find an Iraqi connection to the Sept. 11, 2001, attacks that killed nearly 3,000 people in New York and outside Washington. "I'm quite certain that the president never pushed anybody to twist the facts," she said.

The 10-member commission seemed to split on partisan lines, with the five Democrats sharply challenging Rice. Questions from the Republicans sought to share responsibility for the attack with the previous Clinton administration.

Commissioner Jamie Gorelick, another Democrat, described the FBI's response to the threat in the weeks before the attack as "feckless."

"Yes, the attorney general was briefed but there was no evidence of any activity by him about this," she said. "Have you actually looked at the messages that the FBI put out? To me, and you're free to comment on them, they are feckless. They don't tell anybody anything. They don't bring anyone to battle stations."

Rice said that on entering office in January 2001, the Bush administration fully understood that al Qaeda posed a serious threat. She said Bush was regularly briefed by CIA chief George Tenet and began working immediately to shape a strategy to combat the organization.

"President Bush understood the threat, and he understood its importance. He made clear to us that he did not want to respond to al Qaeda one attack at a time. He told me he was 'tired of swatting flies'," Rice said.

That drew a sharp response from Kerrey. "Can you tell me one example where the president swatted a fly when it came to Al Qaeda prior to 9/11?" he asked.

Rice: "I think he felt that what the agency was doing was going after individual terrorists here and there and that's what he meant by swatting flies."

During what has become known as the "summer of threat," Rice said the government moved to a "high state of alert and activity." But she said the threats were not specific and most indicated the attack would come overseas, especially in the Middle East and North Africa.