WASHINGTON — For the second time this month, the FBI on Monday put out an extraordinary alert warning Americans that it has "credible" reason to believe there could be new terrorist attacks against the United States in the next week.
The threat, though vaguely defined, was considered serious enough that Atty. Gen. John Ashcroft canceled a trip to Toronto Monday afternoon. He also issued an immediate alert to the nation's 18,000 law enforcement agencies, urging them to be extra vigilant in the coming days.
The warning appears to have been triggered in part by concern that cells of Osama bin Laden's Al Qaeda terrorist network remain active and undetected in the United States and could be planning further attacks, according to law enforcement and intelligence sources.
The warning is likely to generate even greater security safeguards at nuclear and electrical plants, sporting events, border crossings, overseas embassies and a host of other sites that could be vulnerable to terrorist attacks, officials said.
Justice Department officials received word early Monday through unspecified channels about the prospect of a fresh round of attacks. They quickly briefed President Bush, who agreed with the decision to put out a public alert, officials said.
"The administration has concluded, based on information developed, that there may be additional terrorist attacks within the United States and against the United States' interests over the next week," Ashcroft told a hastily arranged news conference Monday afternoon. "The administration views this information as credible, but unfortunately it does not contain specific information as to the type of attack or specific targets."
A similar warning put out by the FBI on Oct. 11, believed to have been based on foreign intelligence reports relayed to the CIA, triggered a debate over whether the administration had crossed the precarious line between informing the public and stirring hysteria.
With the spate of recent anthrax attacks, Monday's warning is likely to trigger even greater anxiety than the first alert, less than three weeks ago. FBI Director Robert Mueller said at the news conference that although the intelligence data do not include a specific target or an intended method, he believes that informing the public about even a broad-based threat "could well prevent another terrorist attack."
Ashcroft said that he, too, felt compelled to publicize the threat. "I trust the American people to be able to understand, in this context of conflict, where there is a front overseas and there is another front here in the United States, that they can make good judgments and can understand this kind of information."
Counter-terrorism expert Daniel Benjamin, a National Security Council aide in the Clinton administration, said authorities run the risk of having the public ignore their warnings if they put out too many alerts.
"That's a real danger, but at the same time if you've got a credible source you have to go with it," he said. "It would be politically disastrous if something happened and it was shown afterwards that they had foreknowledge."
In Los Angeles, police said they would reevaluate potential threats in the area and perhaps step up some patrols. But the LAPD essentially will remain on the same heightened alert that it has been on since Sept. 11, when Chief Bernard Parks all but declared a tactical alert, said department spokesman Lt. Horace Frank.
"This is always a concern for us. We are going to assess the information and make a decision as to where we go from here," Frank said. "What the attorney general is asking us to do is identify the credible threat areas within our command and pay close attention to them. We already have been doing that."
While the FBI has put out dozens of narrowly focused warnings since Sept. 11 about crop dusters, trucks carrying hazardous materials and a slew of other potential threats, this is only the second broad nationwide warning that it has issued. Unlike the Oct. 11 warning, which was released as a written statement, both Ashcroft and Mueller appeared at Monday's news conference to announce it.
"It is very extraordinary that they are putting out yet another threat of this nature," said Robert Blitzer, the FBI's former counter-terrorism chief. "For the attorney general and the director of the FBI to get up and do this together, that tells me this is just a very, very serious threat. That just doesn't happen every day."
Counter-terrorism experts said the warning does more than merely inform the public and law enforcement agencies to be on guard. "It puts the bad guys on notice, saying, 'We're on to you,' and it might prevent whatever attack is being planned," Blitzer said.
"What's really prompting all this," said one FBI investigator who asked not to be identified, "is that there is substantial evidence showing that the 19 hijackers were supported by and [were] known to others who remain in the United States, in western Europe and in moderate nations in the Middle East. . . . And there's plenty of reason to believe that there are more people among us who are prepared to be martyrs."
Vince Cannistraro, former counter-terrorism chief for the CIA, agreed.
According to information provided to Cannistraro on Monday by current CIA officials, authorities are clearly concerned that Al Qaeda "still has some people in the United States and they don't know where they are and it has them terrified," Cannistraro said.
"There is a lot of intelligence indicating that people within the United States will hit us, and hit us very hard," he said, adding that U.S. authorities "just don't know the what, and where and when."