In Exercise: US Alert for Terrorist Threats Following bin Laden's Death

Police officers are briefed for a Philadelphia Police Department Homeland Security Unit emergency preparedness exercise in Philadelphia, May 4, 2011 In confirming the death of its leader, Osama bin Laden, the terrorist group al-Qaida is threatening more attacks against the United States and its allies. And top U.S. security officials say they are on alert for possible terrorist retaliation attacks ...Exercise