The memo said al Qaeda leader Osama bin Laden's desire to strike inside America surfaced as long as four years before Mr. Bush took office, according to several people who have seen the memo.
The document has emerged as a key point of interest to the commission investigating the Sept. 11, 2001, airborne attacks on the World Trade Center in New York and on the Pentagon.
Some of the most current information in the so-called presidential daily briefing, or PDB, delivered to Mr. Bush on Aug. 6, 2001, came from reports U.S. intelligence had received in May 2001 about a possible plot for an explosives attack inside the United States, the sources told The Associated Press this week.
Also in August 2001, U.S. intelligence officials received two uncorroborated reports suggesting that terrorists might use airplanes, including one that suggested al Qaeda operatives were considering flying a plane into a U.S. embassy, current and former government officials said.
Those reports - among thousands of varied and uncorroborated threats received by the government each month - weren't deemed credible enough to tell Bush or his national security adviser, Condoleezza Rice, the officials said.
None of the information in the president's briefing or the August reports involved the eventual Sept. 11 plot.
The New York Times and Washington Post are carrying similar reports in their Saturday editions.
The new disclosures seem to contradict the White House's repeated assertions that the information in the memo was mostly "historical" in nature, and that the administration had little reason to suspect a terrorist plot in the works for an attack within the U.S.
Former Indiana Rep. Timothy Roemer, a Democratic member of the Sept. 11 commission, has said: "Something was going to happen very soon and be potentially catastrophic. I don't understand, given the big threat, why the big (national security) principals (officials) didn't get together."
Asked about the AP report, a White House spokesman said the administration stands by its assertions that the memo contains no specific information that could have enabled the government to stop the attacks that took place on Sept. 11, according to CBS News Correspondent Mark Knoller.
The AP sources who read the presidential memo would speak only on condition of anonymity because the White House has yet to declassify the highly sensitive document, titled "Bin Laden Determined to Strike Inside the United States."
The declassification process is expected to be completed by next week, intelligence sources tell CBS News Correspondent Bill Plante.
The declassification would allow the administration to make the document public in an historic disclosure of presidential intelligence briefing materials.
The sources said the memo included a series of bullet items that brought Mr. Bush through a history of mostly uncorroborated intelligence that cited al Qaeda's interest in hijacking planes to win the release of Islamic extremists who had been arrested in 1998 and 1999.
It also included the trips of suspected al Qaeda operatives, including some U.S. citizens, in and out of the United States. It suggested al Qaeda might have a support system in place on U.S. soil, the sources said.
The document also included FBI analytical judgments that some al Qaeda activities were consistent with preparation for airline hijackings or other types of attacks, some members of the commission looking into the Sept. 11 attacks said this week.
The second-to-last bullet told Mr. Bush there were numerous - at least 70 - terror-related investigations under way by the FBI in 2001 involving matters or people on U.S. soil, the sources said.
And the final bullet item, they said, was based on a May 2001 intelligence report indicating al Qaeda operatives were trying to get inside the United States from Canada to carry out an attack with explosives. There were no specifics about the timing or target of the attack, but the memo said the FBI and other agencies were investigating.
A joint congressional inquiry report into Sept. 11 intelligence failures disclosed the May 2001 threat report last year but did not reveal it was included in Mr. Bush's briefing. The congressional inquiry described the intelligence this way:
"In May 2001, the intelligence community obtained information that supporters of Osama bin Laden were reportedly planning to infiltrate the United States via Canada in order to carry out a terrorist operation using high explosives."
In her testimony Thursday to the Sept. 11 commission, Rice described Bush's Aug. 6 daily briefing as including mostly "historical information" and said most threat information in the summer of 2001 involved overseas targets.
Rice also said she did not recall seeing any warnings before Sept. 11 that a plane might be used a terrorist weapon, though it was possible others in the White House did.
Current and former government officials told the AP that in the same month Mr. Bush received his briefing, U.S. intelligence received two uncorroborated reports - among hundreds - suggesting terrorist might use planes but that neither reached the president or Rice.
The officials said one report in August 2001 said there was uncorroborated information that two bin Laden operatives had met in October 2000 to discuss a plot to attack the U.S. Embassy in Nairobi with an airplane.
That report said the operative would either use the plane to bomb the embassy or crash into it, according to information provided congressional investigators and cited in their report released last year.
Separately, the CIA asked the Federal Aviation Administration in August 2001 to advise commercial airlines that six Pakistanis in Latin America, not connected to al Qaeda, were considering a hijacking, bombing or sabotage of an airliner.
That warning did not have specifics on a time or location but said it could involve Britain, Canada, Mexico, Malaysia or Cuba, among others, according to information made public by the congressional inquiry.
Rice said emphatically Thursday she did not see any such reports about al Qaeda using a plane as a weapon until after Sept. 11, suggesting the intelligence may have reached someone lower in the White House.
"To the best of my knowledge ... this kind of analysis about the use of airplanes as weapons actually was never briefed to us," she told the Sept. 11 commission. "I cannot tell you that there might not have been a report here or a report there that reached somebody in our midst."