The U.S. Department of Homeland Security expects "threats of retaliation" from al Qaeda in the aftermath of Osama bin Laden's death

The U.S. Department of Homeland Security expects "threats of retaliation" from al Qaeda in the aftermath of Osama bin Laden's death, a department official told CNN early Monday.
"We certainly anticipate threats of retaliation -- this is an organization that declared war on the United States more than a decade ago -- threats from al Qaeda are not a new phenomenon," the official said.
The development comes as the United States put American diplomatic facilities around the world on high alert and issued a global travel warning for Americans, shortly after President Barack Obama announced that the terrorist leader had been killed in Pakistan.
"Given the uncertainty and volatility of the current situation, U.S. citizens in areas where recent events could cause anti-American violence are strongly urged to limit their travel outside of their homes and hotels and avoid mass gatherings and demonstrations," the State Department said in a worldwide travel warning issued early Monday. "U.S. citizens should stay current with media coverage of local events and be aware of their surroundings at all times."
The Homeland Security official said the agency remains "at a heightened state of vigilance," although the national terror-threat level was not immediately raised following bin Laden's death.
"We remain at a heightened state of vigilance and our security posture, which always includes a number of measures both seen and unseen, will continue to protect the American people from an evolving threat picture both in the next days and beyond," the official said.
"Secretary (Janet) Napolitano has been clear since announcing the NTAS (National Terrorism Advisory System) in January that we will only issue alerts when we have specific or credible information to convey to the American public," the official said.
The range of precautions comes as the United States braces for potential retaliatory attacks in the aftermath of bin Laden's death at the hands of U.S. special forces.
Adding to the concern is a Defense Department report released last week by the WikiLeaks website that a Guantanamo detainee had knowledge of al Qaeda possibly possessing a nuclear bomb somewhere in Europe.
The detainee, Abu al-Libi, said he was told by al Qaeda associate Sharif al-Masri that he believed if bin Laden were captured or killed "the bomb would be detonated" in the United States.
Al-Libi said al-Masri told him during the summer of 2004 that the terrorist network was having difficulty moving the bomb, but if it could move it "al Qaeda would find operatives to use it."
Local authorities also took precautions.
In New York, where a pair of hijacked commercial jetliners took down the twin towers of World Trade Center on September 11, 2001, police were wary.
"While there is no information indicating a specific threat to New York City, members of the service are reminded to remain alert in the aftermath of the announcement that Osama bin Laden has been killed," New York Police Commissioner Raymond Kelly said.
The Philadelphia Police Department said it was doing hourly checks on mosques and synagogues, following the president's address, according to Lt. Raymond Evers.