WASHINGTON -- Anti-aircraft missiles guarded Washington's skies and Capitol police carried gas masks Wednesday as the nation mobilized against a potential terrorist attack.
Federal, state and local governments tightened security, anxious Americans stockpiled food and water, and police responded to scores of false alarms, including reports of suspicious vehicles that shut down commuter bridges in Washington and New York.
The nation remained under a Code Orange "high risk" of attack status for a sixth day, and no change was in sight. Counterterrorism officials said the level of threat information pointing to an imminent attack remained high, but steady.
"If given the choice, al-Qaida terrorists will choose attacks that achieve multiple objectives, striking prominent landmarks, inflicting mass casualties, causing economic disruption and rallying support through shows of strength," CIA Director George Tenet told the Senate Armed Services Committee.
Meanwhile, U.S. counterterrorism officials were reviewing a transcript of a second purported audio message from bin Laden, but they could not verify it was an authentic message from the terror chief.
While the speaker mentions an apparent intention to die in the coming year and uses some rhetoric similar to bin Laden's, officials said they could not be certain of the speaker's identity without reviewing the actual recording. The officials spoke on condition of anonymity.
Fearing the worst, U.S. officials deployed Avenger anti-aircraft missiles and extra radar around Washington since President Bush's decision Friday to raise the alert status from yellow to orange, the second-highest level. The Air Force has stepped up its combat air patrols over the capital, defense officials said.
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.
U.S. 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.
The weekly FBI bulletin circulated to 17,000 law enforcement agencies urges police to be extra vigilant for possible chemical, biological and radiological attacks. The bulletin asks 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.
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 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.
On the so-called bin Laden tape, which was a major source of concern, the voice tells bin Laden's followers to help Saddam Hussein stage suicide attacks and lure American troops into bloody urban battles to inflict "big casualties." The speaker said Iraq was governed by socialist "infidels, including Saddam, but said it was acceptable for Muslims to fight for Iraq because their interests "intersect in fighting against the Crusaders," or Christians.
Even without further evidence or confirmation that the voice was bin Laden's, White House spokesman Ari Fleischer seized on the tape as evidence that Saddam and al-Qaida are linked.
"This is the nightmare that people have warned about, the linking up of Iraq with al-Qaida," Fleischer said, denouncing what he called "an unholy partnership."
The tape was released Tuesday, just as Bush was trying to build public opinion against Saddam.
Fleischer expressed far less alarm about North Korea's aggressive actions, reflecting Bush's desire to keep attention on Iraq. As Fleischer briefed reporters, Tenet was telling lawmakers that Pyongyang has an untested ballistic missile capable of reaching the western United States.
Fleischer dismissed the testimony as "old news," and said it explains Bush's desire to build an anti-missile shield.