Numerous officials familiar with the information cautioned Thursday night that while the threat is specific and worrisome, it is based on raw intelligence that is unconfirmed. Law enforcement agencies across the Eastern Seaboard were scrambling to determine how serious the danger is and to find any possible terrorist plotters.
Yet the mere prospect of an attack to coincide with such a sacred anniversary sparked jitters in New York and Washington, where President Obama was briefed Thursday morning and updated throughout the day, even as he prepared to address a joint session of Congress.
Members of Congress were also briefed on what law enforcement and intelligence officials described as the first specific and credible threat related to the anniversary of the attacks on the World Trade Center and the Pentagon. The concern was amplified by the knowledge that before he was killed in May, Osama bin Laden had seemed fixated on attacking the United States again on or around Sept. 11.
“As we know from the intelligence gathered from the [bin Laden] raid, al-Qaeda has shown an interest in important dates and anniversaries, such as 9/11,’’ said Matthew Chandler, a spokesman for the Department of Homeland Security. “In this instance, it’s accurate that there is specific, credible but unconfirmed threat information.’’
“We continue to ask the American people to remain vigilant as we head into the weekend,’’ he said.
The new intelligence came as security was already being ramped up nationwide, particularly in New York, where Obama and former president George W. Bush are scheduled to mark the anniversary on Sunday at Ground Zero inside what police call a “frozen zone.’’ Police are planning to cordon off the area for several blocks in all directions, forcing even residents to be escorted by police officers to their apartments.
With the latest news, officials vowed Thursday night to tighten security even further.
New York authorities said they would reinforce patrols across the city, paying special attention to bridges, tunnels and other transportation hubs, and use even more bomb-sniffing dogs.
“Over the next few days, we should all keep our eyes wide open,’’ Mayor Michael R. Bloomberg (I) said at a news conference. But he urged New Yorkers not to change their daily routines, vowing that he would take the subway to work Friday morning.
In Washington, Police Chief Cathy L. Lanier said the public should expect increased security measures and more stopped vehicles.
Police officials activated 12-hour shifts in response to the possible threat and will continue the extended duty indefinitely, officials said. Officers will be passing out fliers to city businesses and storefronts, advising the public to alert authorities about abandoned or suspicious vehicles or suspicious people who are loitering.