WASHINGTON – Citizens nationwide were stocking up on supplies and taking terror precautions Thursday after an audio tape attributed to Usama bin Laden urged Muslims to stage homicide attacks against Americans.
Meanwhile, a report surfaced Wednesday of an additional audio recording by bin Laden in which the Al Qaeda leader purportedly predicts his own death in an unspecified act of "martyrdom" against the United States.
Al-Ansaar, a British-based Islamic news agency, said it believed the 53-minute tape, allegedly recorded earlier this month and acquired from an unidentified man on the Internet, was a carefully worded last will and testament from bin Laden.
U.S. counterterrorism officials said they were reviewing a transcript of the tape but could not verify its authenticity without hearing the actual recording.
In an earlier tape released Tuesday by the Al-Jazeera television network, the terror mastermind told Muslims to unite against the United States if war breaks out in Iraq.
CIA Director George Tenet told the Senate Armed Services Committee Wednesday that he is worried that the previous bin Laden message is a prelude to a strike.
"He's obviously raising the confidence of his people. He's obviously exhorting them to do more," Tenet said. "What he's said is often followed by an attack."
Officials in Washington have been warning that a possible terror attack against Americans could coincide with Thursday's end of the annual Muslim pilgrimage to Mecca.
In New York, hospitals were placed on high alert based on government intelligence of a potential threat, naming cyanide as the specific terror agent.
NYU Medical Center's Chief Medical Officer Eric Rackow wrote in a staff memo Wednesday that the hospital was taking all necessary precautions.
"NYU is working to ensure that we have adequate levels of the proper antidotes and pharmaceutical agents to treat patients should they be exposed to cyanide," Rackow wrote.
The New York Post reported Thursday that sensors that can sniff out deadly biological and chemical agents are being tested in the city’s subway system. The shoebox-sized devices, which have been installed in hidden locations at several major stations across the city, are like fire alarms and would sound a quiet warning in the event of a terrorist attack.
The sensors continuously suck in air and analyze it and are similar to biochemical sensors recently installed at 10 stations in the Washington, D.C., subway system.
If tests prove successful, New York transit officials will move to expand the program.
In New York on Thursday, National Guardsmen stood watch under the vaulted ceiling of Grand Central Terminal. Police with bomb-detecting dogs scanned the crowd.
Bill McCaffrey took it all in stride.
"Something may happen, something may not," the ad agency employee said. "You can worry about that on every street corner. It's part of living in New York."
In Michigan, officials stepped up security at more than 300 synagogues and Jewish institutions after the FBI warned about possible Al Qaeda attacks on Jews.
"When a threat like this comes in, we go into alert mode and we make sure that every Jewish organization in the state is notified," Betsy Kellman, Michigan head of the Anti-Defamation League, told the Detroit Free Press.
She said the front doors now are locked at most Michigan synagogues and religious schools, as well as at many of the Jewish social agencies. Visitors' identification is being checked and surveillance has been increased, she said.
The weekly FBI bulletin circulated to 17,000 law enforcement agencies urged police to be extra vigilant for possible chemical, biological and radiological attacks. The bulletin asked local officials to consult a CIA handbook on how to respond to dangerous substances should such an attack occur.
In addition, the National Infrastructure Protection Center, which assesses and warns about threats to critical U.S. infrastructure, issued an advisory describing a heightened chance of global computer hacking as tensions increase with Iraq.
Authorities have also been responding to dozens of false alarms of suspicious vehicles. Some of the calls prompted the shutdown of bridges in New York and Washington.
The U.S. remained under a Code Orange "high risk" of attack status for a seventh day, and no change was in sight. Counterterrorism officials said the level of threat information pointing to an imminent attack remained high, but steady.
FBI personnel assigned to rapid response teams that would react to any terrorist attacks have been told to have a bag packed for three days' deployment and put on standby.
Anti-aircraft missiles guarded Washington's skies and Capitol police were told to carry gas masks at all times. They are in a small, handheld black knapsack about six inches long. Every officer has them, including those in plainclothes who provide security for leaders and in the congressional chambers.
White House security was not noticeably tighter but presidential aides said they were spooked by the intelligence and felt more vulnerable than they had since the Sept. 11, 2001, attacks. Many were taking the government's advice, socking away water and food at home and making plans to meet up with family in the event of an attack.
Precautions were taken throughout the federal government. For example:
— Food safety officials were put on heightened alert but were told the threat did not involve food, said Agriculture Department spokesman Steven Cohen.
— Nuclear power plant operators were issued reminders of precautions they should take under a Code Orange.
— The Interior Department's Bureau of Reclamation has increased security at its 58 hydroelectric dams and 348 reservoirs that serve 31 million people in 17 Western states. Precautions include limiting access, closing visitors centers and some roads and conducting random vehicle inspections at some facilities.
To prepare for a potential chemical or biological attack, the Federal Emergency Management Agency advises Americans on its Web site to purchase battery-powered radios, duct tape, scissors and plastic sheeting to cover doors, windows and vents. The agency also suggests stocking up on food and drinking water.
Citizens apparently were paying attention. Hardware stores and food clubs were reporting an increase in sales. And stores like Home Depot were bringing in more supplies to meet the demand.
"If given the choice, Al Qaeda terrorists will choose attacks that achieve multiple objectives, striking prominent landmarks, inflicting mass casualties, causing economic disruption and rallying support through shows of strength," Tenet said.
White House spokesman Ari Fleischer said the tape linked to bin Laden was evidence that Saddam and Al Qaeda are linked.
"This is the nightmare that people have warned about, the linking up of Iraq with Al Qaeda," Fleischer said, denouncing what he called "an unholy partnership."
But in both the nation's capital and the Big Apple, many people said they were unafraid and determined to go about their lives.
"I'm not changing our lifestyle," said Liz Davis, 43, of Alexandria, Va., who said she has plenty of food at home but has not taken other emergency steps. "Part of living near D.C. is living at a ground zero of sorts. It's part of the package."
"I find people heed the snow alerts more than terror alerts," choreographer Mindy Cooper said as she walked her dog in Central Park.
Fox News' Heather Nauert and The Associated Press contributed to this report.