The United States has said that Al-Qaeda and its leaders continue to pose threat. Chairman of the US Joint Chiefs of Staff, Admiral Mike Mullen in a news conference at Pentagon said that Washington is committed to hunt down Ayman al-Zawahiri, the new Al Qaeda leader, the same way as that of his predecessor Osama bin Laden, who was killed. Mullen said he was not surprised by the news reports that Zawahiri has succeeded Osama bin Laden.