During the presidential transition, Clinton administration officials briefed Bush national security personnel, but a spokesman Monday said they did not receive an aggressive plan for toppling al Qaeda, reports CBS News Correspondent Mark Knoller, traveling with the president.
An official said one such plan was drafted during the early days of the Bush administration, but was only ready for presentation to the president on Sept. 10, a day before the attacks.
A report in the Aug. 12 issue of Time magazine said the current administration's review of its predecessor's briefings became bogged down in bureaucracy.
Time magazine reporter Massimo Calabresi says the Bush administration cannot claim to have moved quickly on the plan's covert elements.
"They initiated a policy review that would not get its first hearing from top decision-makers until the last days of April," Massimo said Monday on the CBS News Early Show, adding that top security officials didn't hold a meeting until Sept. 4.
Calabresi said the Clinton administration didn't have time to implement the plan.
"The top national security officials in the Clinton administration were briefed on it in late December (2000), and they decided because it did involve a relatively aggressive covert action that they should defer to the incoming administration," he told anchor Jane Clayson.
The current White House denies receiving any firm plans for dealing with al Qaeda.
"The Clinton administration did not present an aggressive new plan to topple al Qaeda during the transition," said White House spokesman Sean McCormack. "We were briefed on the al Qaeda threat and what the Clinton administration was doing about it. These efforts against al Qaeda were continued in the Bush administration."
According to Time, Mr. Clinton's anti-terror czar, Richard Clarke, offered detailed proposals: arresting al Qaeda personnel, choking off the group's financing, aiding nations fighting the organization and beefing up covert action in Afghanistan to deny al Qaeda sanctuary.
Clarke, who stayed on in the Bush administration, also called for a substantial increase in support for the Northern Alliance in Afghanistan and for planning of air strikes on Afghan terror camps.
But a senior Bush administration official said Sunday the Clinton White House offered the incoming Bush team only ideas on how to "roll back" the threat over a three- to five-year period.
Soon after it began studying the issue, the Bush administration decided a "rollback" was inadequate, and began planning for eliminating al Qaeda altogether, said the official, speaking on condition of anonymity.
In the first few days of the Bush White House, national security adviser Condoleezza Rice asked for proposals for major presidential policy review and, based on a response from Clarke, ordered a review of policy toward al Qaeda, the senior official said.
Top Bush administration officials approved what McCormack called the "comprehensive strategy to eliminate al Qaeda" exactly one week before the Sept. 11 attacks.
Could the Sept. 11 attacks have been eliminated if the Clinton administration plan had been implemented earlier? Calabresi said it is impossible to say for certain.
"Plenty of people we talked with said that, from their perspective, this wouldn't have made a difference because several of the plotters were already in place in the United States," he said. "They were in flight schools and so on."
Time Magazine also reports that while concern was mounting by last summer that a major terrorist attack against U.S. interests was imminent, no decision was made to send a Predator drone - the best possible source of intelligence on the terror camps run by Osama bin Laden - to fly over Afghanistan.
"The Predator sat idle from October 2000 until after September 11," Time reported.
"The Predator was not flown because we were in the final stages of developing new capabilities for it," said a senior Bush administration official, commenting anonymously. The official declined to describe the new capabilities, which could have included arming the drone.
Questions about the Bush administration's planning against al Qaeda come on top of disclosures that American intelligence officials intercepted communications in Arabic that made vague references to an impending attack on the United States. They contained the phrases, "Tomorrow is zero hour" and "The match is about to begin."
The intercepts weren't translated until Sept. 12. Their relevance is uncertain.