If we are killed, you will be killed.
A video released Monday by al Qaeda showed Ayman al-Zawahiri, Osama bin Laden’s chief aide, threatening American troops.
The treat comes after President George W. Bush’s plan to increase troop involvement in Iraq by 20,000.
"If we are secure, you might be secure, and if we are safe, you might be safe. And if we are struck and killed, you will definitely -- with Allah's permission -- be struck and killed," al-Zawahiri said.