The Pentagon released audio Thursday of a military tribunal at Guantanamo Bay where Khalid Sheikh Mohammed confessed to being behind the Sept. 11 attacks and killing American journalist Daniel Pearl.

"I was responsible for 9/11 from A to Z," Mohammed said in a written statement read at the closed court session. "I decapitated with my blessed right hand the American Jew, Daniel Pearl in Karachi."

Mohammed portrayed himself as Al Qaeda's most active operational planner, confessing to playing a central role in 30 other attacks and plots in the U.S. and worldwide that left scores dead.

'I was responsible for the bombing of a night club in Bali, Indonesia, which was frequented by British and Australian nationals,' the statement said. "I was responsible for the assassination attempt on President Clinton during his visit to the Philippines in 1994 or 1995."

Click here to read the full testimony transcript (pdf).

The Pentagon posted a link containing 30 minutes of audio from the tribunal, held to determine whether Mohammed should be declared an "enemy combatant," but withheld an additional 10 minutes of testimony over fears it could be used as propaganda.

The full transcript of the hearing released months ago shows that the Pentagon censored testimony where Mohammed confessed to pledging allegiance to Usama bin Laden and explaining why Islamic militants waged Jihad against America.

Also cut was a clip where Mohammed compared himself and bin Laden to George Washington and expressed sorrow over Sept. 11.

"We and George Washington doing the same thing," Sheikh Mohammed told the tribunal in broken English.

"I'm not happy that 3,000 been killed in America," the transcript quoted him as saying. "I feel sorry even. I don't like to kill children and the kids."

Click here to read a summary of the evidence presented at the hearing(pdf).

Officials from the CIA, FBI, State Department and others listened to the audio and feared some it could be copied and edited by other militants for use as propaganda, officials said.

"It was determined that the release of this portion of the spoken words of Khalid Sheikh Mohammed would enable enemies of the United States to use it in a way to recruit or encourage future terrorists or terrorist activities," said Pentagon spokesman Bryan Whitman. "This could ultimately endanger the lives and physical safety of American citizens and those of our allies."

Other portions were cut because of security concerns, officials said.

During much of Mohammed's hearing, he spoke in English. The released audio includes Mohammed responding to questions.

Audio tapes of other high-value detainees have been released by the Pentagon.

Mohammed was the first of 14 so-called "high-value" detainees who were held in secret CIA prisons before being transferred to the Pentagon facility at the U.S. naval base in Guantanamo Bay, Cuba.

Since the March hearing, Mohammed has been assigned "enemy combatant" status, a classification the Bush administration says allows it to hold him indefinitely and prosecute him at a military tribunal.

The Associated Press contributed to this report.