It's a fresh credibility issue for the adviser whose remarks about prewar Iraq information also have been questioned by members of Congress.
President Bush's adviser told the public in May 2002 that a pre-Sept. 11 intelligence briefing for the president on terrorism contained only a general warning of threats and largely historical information, not specific plots, the report said.
But the authors of the congressional report, released last week, stated the briefing given to the president a month before the suicide hijackings included recent intelligence that al-Qaida was planning to send operatives to the United States to carry out an attack using high explosives.
The White House defended Rice, saying her answers were accurate given what she could state publicly at the time about still-classified information and that Bush retains full confidence in Rice.
"She is strongly committed with the president to making America safer," White House spokesman Scott McClellan told reporters.
The Sept. 11 congressional investigators underscore their point three times in their report, using nearly identical language to contrast Rice's answers with the actual information in the presidential briefing.
Bush's daily briefing on Aug. 6, 2001, contained "information acquired in May 2001 that indicated a group of [Osama] bin Laden supporters was planning attacks in the United States with explosives," the report said.
A footnote to that passage compares the information with what Rice told the public at a May 16, 2002, news conference.
Rice "stated, however, that the report did not contain specific warning information, but only a generalized warning, and did not contain information that al-Qaida was discussing a particular planned attack against a specific target at any specific time, place, or by any specific method," the footnote said.
At the same May 2002 press briefing, Rice also said that "I don't think anybody could have predicted that these people would take an airplane and slam it into the World Trade Center, take another one and slam it into the Pentagon; that they would try to use an airplane as a missile, a hijacked airplane as a missile."
But the congressional report states that "from at least 1994, and continuing into the summer of 2001, the Intelligence Community received information indicating that terrorists were contemplating, among other means of attack, the use of aircraft as weapons."
The report says that Rice and other top officials seemed unaware of the intelligence and concludes the information must not have been widely circulated.