Bin Laden: Americans Will Die if Alleged 9/11 Mastermind Is Executed

File: Al Qaeda leader Usama bin Laden in Afghanistan. (AP)

Al Qaeda leader Usama bin Laden threatened in a new audio recording released Thursday to kill any captured Americans if the U.S. executes the accused mastermind of the Sept.11 attacks or any other Al Qaeda suspects.

The U.S. is still considering whether to put Khalid Sheik Mohammed and four of his fellow plotters on military tribunal for their role in the Sept. 11 attacks. The Obama administration is also looking into recommendations for civilian trials, and is expected to announce a decision soon.

In a brief 74-second audio tape aired on Al-Jazeera television, bin Laden said if the U.S. decides to execute any Al Qaeda suspects in its custody -- and explicitly mentioned Mohammed -- his terror network would kill American captives.

The terror leader said such a decision "would mean the U.S. has issued a death sentence against whoever of you becomes a prisoner in our hands."

"Your friend at the White House is still walking in the footsteps of those before (him) in many important matters," including escalating the war in Afghanistan and "oppressing our prisoners that you are holding, beginning with the mujahid hero Khalid al Sheikh Mohammed," he added.

U.S. politicians have "oppressed us and still do, especially by backing Israel, which occupies the land of Palestine," the Al Qaeda chief said.

It was not immediately clear whether Al Qaeda currently has any U.S. captives, but the Haqqani group -- the Pakistan-based Taliban faction closest to Al Qaeda -- is holding an American soldier it captured in eastern Afghanistan in June 2009. It released a video of him in December.

In a veiled threat, bin Laden said Americans had previously thought their homeland was beyond the reach of his group until the 9/11 attack.

Mohammed, who was captured in Pakistan in 2003, is the most senior Al Qaeda operative in U.S. custody, and is currently in detention at the U.S. naval base at Guantanamo Bay, Cuba. In 2008, the U.S. charged him with murder and war crimes in connection with the Sept. 11 attacks. Pentagon officials have said they'll seek the death penalty.

"It's the height of absurdity for anyone associated with Al Qaeda to even suggest that now, at long last, they're going to start treating captives badly. They may have forgotten Danny Pearl and all the others they've slaughtered, but we haven't," a U.S. counterterrorism official said in response to the newest message.

"If this is bin Laden and he wants to weigh in on legal proceedings involving 9/11 conspirators, I challenge him to show up in court to make his case. Frankly, that's about all the comment this deserves."

The Associated Press contributed to this report.