Despite White House avowals that it would have been impossible to conceive before September 11th of a hijacked plane being used to attack US targets, a 1999 report for the CIA envisioned a very similar threat.
It predicted Islamic militant Osama bin Laden would retaliate "in a spectacular way" against Washington for US cruise missile strikes in 1998 against training facilities of his al Qaeda network in Afghanistan.
"Suicide bombers belonging to al Qaeda's martyrdom battalion could crash-land an aircraft packed with high explosives ... into the Pentagon, the headquarters of the Central Intelligence Agency, or the White House," the report said.
The report was commissioned by The National Intelligence Council, which reports to CIA Director George Tenet. It was conducted by the research arm of the Library of Congress, well before Mr Bush took office.
One work in a vast output of terrorism studies, the report has long been public and is available on the Internet. (http://www.loc.gov/rr/frd/Sociology-Psychology%20of%20Terrorism.htm)
But its on-target prediction prompted new questions over how much the US government knew about potential threats, in the wake of disclosures that President Bush was alerted in his daily CIA intelligence briefing last August to the possibility of a hijacking by al Qaeda.
"I don't think anybody could have predicted that these people would take an airplane and slam it into the World Trade Centre, take another one and slam it into the Pentagon," Mr Bush's national security adviser, Condoleezza Rice, said Thursday.
White House spokesman Mr Ari Fleischer said on Thursday the alert to Mr Bush did not say there was a chance planes would be used by al Qaeda as suicide bombs.
Yesterday Mr Fleischer played down the significance of the report, saying it was primarily a study of the thinking of potential terrorists and not based on specific intelligence.
He said he had not learned of the report until yesterday, but noted it had also long been available to Congress, some of whose members have called for an investigation into potential administration intelligence failures.