America's top military officer says the United States will hunt down and kill the new leader of al Qaeda, just as it did with Osama bin Laden.
The chair of the Joint Chiefs of Staff, Admiral Mike Mullen, says he is not surprised by the choice of Egyptian militant Ayman al-Zawahiri to succeed bin Laden, who was killed in a US raid in Pakistan last month.
Admiral Mullen says America will show him no mercy.
