U.S. officials, who released the tape, pointed to bin Laden's words as compelling evidence that he had masterminded the Sept. 11 attacks. Officials said that while they have never doubted bin Laden's guilt, they hoped that the tape would dispel any lingering public skepticism.
"I was the most optimistic of them all," he says, adding that the destruction of three or four floors was "all that we had hoped for."
Bin Laden recalls that upon hearing of the first attack, he informed his companions that further attacks would follow.
"They were overjoyed when the first plane hit the building," he said. "So I said to them: 'Be patient.'"
On the tape, which the Bush administration said was found in a house in Jalalabad after the Afghan city fell to opposition forces, bin Laden seems delighted as he recounts the terrorist attacks.
The tape is amateurish, with voices often inaudible and further obscured by sounds of heavy breathing. But the broadcast version, which was accompanied by an English-language translation, offers a window into the thoughts of the leader of the al-Qaida network.
Bin Laden appears in a room with several followers. U.S. officials said they believe the videotape was made in mid-November in a guesthouse in the Taliban's former stronghold of Kandahar.
Sitting on the floor before a white wall, bin Laden tells his compatriots that he thought burning jet fuel would melt only enough steel to destroy three or four floors in each World Trade Center tower and not cause the entire building to collapse.
President Bush viewed the tape for the first time Nov. 30, the White House said, but decided not to release it until intelligence analysts had deemed it authentic and experts had had time to translate the dialogue.
The Pentagon said U.S. officials wanted to balance "the concerns about any additional pain that could be caused by its release against the value of having the world fully appreciate what we are up against in the war against terrorism."
In the 39-minute dialogue, bin Laden appears with several aides and a visiting Saudi cleric, identified by U.S. officials as Sheik Sulayman. Sulayman, whose contentment with the attacks is as obvious as bin Laden's, suggests ominously: "Allah has bestowed ... honor on us ... and he will give us blessing and more victory during the holy month of Ramadan."
Most Muslims in the United States will mark the end of Ramadan on Sunday.
The sheik praises bin Laden for a "clear victory," telling him he did a "great job." He tells bin Laden that he witnessed joy resulting from the attacks that was comparable to watching a soccer game when "your team wins."
Bush administration officials and members of Congress were eager to portray the tape as undeniable evidence of bin Laden's guilt. U.S. officials said they hope the tape, which was broadcast by several television stations in the Arab world, will help build support among Muslims who have been skeptical of the evidence against bin Laden.
White House spokesman Ari Fleischer said Bush "has known all along that Osama bin Laden has been behind this." Fleischer said "it came as no surprise to the president that Osama bin Laden would be taking responsibility and having advance knowledge of the attack."
"How can there be a doubt in anyone's mind any longer about what we have said from the very, very beginning - that he was the mastermind?" asked Secretary of State Colin L. Powell. "Everybody can make their [own] judgment," he said, "but I don't know what other judgment one can make about it."
Bin Laden, who seems aware that he is being filmed, does not explicitly claim responsibility for the attacks but recalls his involvement with pride. He appears bemused as he boasts that at least some of the hijackers initially had known only that they were going to the United States on a "martyrdom operation."