"I decapitated with my blessed right hand the head of the American Jew, Daniel Pearl, in the city of Karachi, Pakistan," Mohammed is quoted as saying in a transcript of a military hearing at Guantanamo Bay, Cuba, released by the Defense Department.
"For those who would like to confirm, there are pictures of me on the Internet holding his head," he added.
Mohammed's claimed involvement in the 2002 slaying of the Wall Street Journal reporter was among 31 attacks and plots — some of which never came to fruition — he took responsibility for in a hearing Saturday at the U.S. naval prison at Guantanamo Bay, Cuba, the Pentagon said.
It released the bulk of the transcript late Wednesday, but held back the section about Pearl's killing to allow time for his family to be notified, said Defense Department spokesman Bryan Whitman.
Sealing a legacy of historical notoriety, Mohammed portrayed himself as al Qaeda's most ambitious operational planner in a confession to a U.S. military tribunal.
The Guantanamo Bay hearing, known as a Combatant Status Review Tribunal, is a formality allowing the military to certify a detainee as an "enemy combatant" who warrants further detention and can be prosecuted by a military tribunal. In Mohammed's case, "For sure, I'm American enemies," he said. "I don't have anything to say that I'm not enemy," reports CBS Evening News producer Phil Hirshkorn.
Mohammed's language offers what CBS news consultant Paul Kurtz says is a fascinating insight into the mastermind behind Sept. 11.
"He is a warrior, and he's taking on his enemy the way he sees fit," Kurtz tells CBS News national security correspondent David Martin. "He's sorry about losing 3,000 people over the World Trade Center attacks. Nonetheless, this is the language of war. He says that several times in the transcript."
Many plots, including a previously undisclosed plan to kill several former U.S. presidents, were never carried out or were foiled by international counterterrorism authorities.
"I was responsible for the 9/11 operation from A to Z," Mohammed said in a statement read Saturday during a Combatant Status Review Tribunal at the U.S. detention facility at Guantanamo Bay, Cuba. Mohammed's confession was read by a member of the U.S. military who is serving as his personal representative.