BRUSSELSNEW YORK CAIROBROWNSVILLE, Tenn. — - Osama bin Laden threatened in a new message released Thursday to kill any Americans al-Qaida captures if the U.S. executes the self-professed mastermind of the Sept. 11 attacks or other al-Qaida suspects. In the 74-second audiotape aired on Al-Jazeera television, the al-Qaida leader explicitly mentions Khalid Sheikh Mohammed, who was captured in Pakistan in 2003. He is the most senior al-Qaida operative in U.S. custody and is currently detained at the U.S. naval base at Guantanamo Bay, Cuba. In 2008, the U.S. charged Mohammed with murder and war crimes in connection with the Sept. 11, 2001 attacks on the U.S. Pentagon officials have said they will seek the death penalty for him. Four of his fellow plotters are also in custody. "The White House has expressed its desire to execute them. The day America makes that decision will be the day it has issued a death sentence for any one of you that is taken captive," bin Laden said.