The SITE Institute Web Site reportedly has a five-minute long recording in Arabic that has bin Laden speaking of the Sept. 11 attacks and Moussaoui.
Bin Laden's alleged voice claims responsibilities to carry out the attacks were given to 19 men and Moussaoui was not one of them.
"He had no connection at all with Sept. 11," the voice said. "I am the one in charge of the 19 brothers and I never assigned brother Zacarias to be with them in that mission."
"Since Zacarias Moussaoui was still learning how to fly, he wasn't No. 20 in the group, as your government has claimed," bin Laden continued.
Bin Laden claims that Moussaoui was not a security risk for Al Qaeda, because he had no knowledge of the plot.
"Brother Moussaoui was arrested two weeks before the events (of Sept. 11, 2001), and if he had known something — even very little — about the Sept. 11 group, we would have informed the leader of the operation, Mohammad Atta, and the others ... to leave America before being discovered," he said on the tape.
The new tape is "propaganda plain and simple," a U.S. intelligence official told FOX News on the condition of anonymity.
That official also said the message is part of bin Laden's continuing effort to demonstrate he is a relevant extremist leader, who is knowledgeable of current events, even if his terror organization has become fractured.
Bin Laden also commented on the U.S. prison in Guantanamo Bay, Cuba, saying that none of the hundreds of terror suspects held there were involved in the attacks and most had no ties to Al Qaeda.
"Our brothers in Guantanamo ... have no connection whatsoever to the events of Sept. 11," he said, adding that "some of them oppose Al Qaeda's methods of calling to fight America."
In one phrase, the terror mastermind did indicate that two suspects had links to Sept. 11. But he did not provide names or elaborate further and it wasn't possible to determine if or where they were held.
"All the prisoners to date have no connection to the Sept. 11 events or knew anything about them, except for two of the brothers," bin Laden said.
He did mention by name two journalists and a relief worker accused of having links to Al Qaeda, saying they had no such ties. Sami al-Hajj, an Al-Jazeera cameraman, was arrested in Afghanistan in 2001 and held at Guantanamo Bay. Tayssir Alouni, an Al-Jazeera correspondent, was convicted by a Spanish court in September 2005 of collaborating with Al Qaeda, though he denied the charges. The Al Qaeda leader also mentioned Abdul Aziz al-Matrafi, founder of an Afghan charity branded by the U.S. as supporting terror.
For U.S. officials, the tape is not entirely unexpected. Leading up to the Moussaoui verdict, the government was monitoring Jihadist Web sites in anticipation of a response to the jury's decision.
Moussaoui was sentenced to life in prison earlier this month after a jury ruled that the self-professed Al Qaeda member was responsible for at least one death on Sept. 11. A jury could not agree on a death sentence unanimously, so a life sentence was imposed under federal law.
But bin Laden said Moussaoui's confession that he helped plan the attacks was "void," calling it the result of "pressures exercised against him during four and a half years" in U.S. prison.
Edward MacMahon, one of the lawyers who defended Moussaoui during his death penalty trial, said bin Laden wouldn't have made the best witness for his client, even with his statements that Moussaoui had no role in the attacks.
"I'm not commenting on the credibility of Usama bin Laden," MacMahon said. "I never believed there was any evidence to support Moussaoui's story (that he was the 20th highjacker), and that's what I told the jury."
The tape will be analyzed by the government, which shouldn't take long, since the intelligence community has a large collection of tapes from bin Laden for voice comparison. The intelligence official told FOX News that "there is no reason to doubt the tapes' authenticity," considering there has never been a fake bin Laden audiotape.
If authentic, it would be the third by bin Laden this year. In a tape aired on Arab television in April, he denounced the United States and Europe for cutting off funds to the Hamas-led Palestinian government, accusing them of leading a "Zionist" war on Islam, and urged followers to fight any U.N. peacekeeping force in Sudan.
In January, bin Laden said in an audiotape that Al Qaeda was preparing new attacks in the United States but offered a truce — though his lieutenant Ayman al-Zawahiri later issued a video saying Washington had refused to take the offer.
The January message was bin Laden's first in over a year, his longest period of silence since the Sept. 11, 2001, attacks in the United States.
His deputy al-Zawahri releases messages more frequently, appearing in videotapes, while bin Laden has not appeared in a video since October 2004.
The Associated Press contributed to this report.