In a 74-second audio message released on Thursday, Osama bin Laden threatened to kill any Americans held by Al Qaeda if Khalid Shaikh Mohammed, the chief planner of the Sept. 11 attacks, is executed.
American counterterrorism officials said they thought the recording, addressed to the American people and broadcast on Al Jazeera television, was authentic.
Mr. bin Laden denounced the United States for imprisoning Qaeda members, “first and foremost among them the holy warrior and hero, Khalid Shaikh Mohammed,” according to a translation by the Middle East Media Research Institute in Washington.
“The White House declared that it wanted to execute them,” Mr. bin Laden said. “The day the United States makes this decision, it will have made the decision to execute those of you who fall prisoner to us.”
The message was undated, but it appeared to be referring to statements in recent months by Obama administration officials that Mr. Mohammed, who is awaiting trial on murder charges, is likely to be convicted and executed. The officials were defending the administration’s initial plan, now under review, to give five people accused of being Sept. 11 conspirators civilian criminal trials.
Asked in an interview with NBC News in November about Americans who were offended that Mr. Mohammed would get the same rights as any other criminal defendant, President Obama said such critics would not find it “offensive at all when he’s convicted and when the death penalty is applied to him.” He added that he was not trying to prejudge the outcome of any trial.
Attorney General Eric H. Holder Jr. and the White House spokesman, Robert Gibbs, have made similar statements.
Since January, when New York City officials objected to the disruption and cost of a trial for Mr. Mohammed in federal court in Manhattan, the administration has been considering its options. Opponents of a criminal trial have called for the suspects to face military commissions at the prison in Guantánamo Bay, Cuba, where they are now being held.
In the new recording, Mr. bin Laden repeated a recurrent theme of Qaeda messages since Mr. Obama’s election: that he had not reversed the policies toward the Muslim world of former President George W. Bush. “Your master in the White House continues to follow in the footsteps of his predecessor in many important matters, like his escalation of the war in Afghanistan,” Mr. bin Laden said.
No Americans are known to be held directly by Al Qaeda, officials said, though Taliban fighters are believed to be holding Pfc. Bowe R. Bergdahl, who was kidnapped after walking off his Army base in southern Afghanistan last summer.
An American counterterrorism official who discussed the bin Laden statement on the condition of anonymity called it the “height of absurdity” for Al Qaeda to threaten now to harm captives, given that the group’s operatives have routinely tortured and beheaded prisoners, including the American journalist Daniel Pearl in 2002.
Obama Team Is Divided on Tactics Against Terrorism