FBI - Attack threat credible

WASHINGTON -- For the second time this month, the FBI warned Americans on Monday that terrorists could strike here or abroad, possibly this week. The new alert was based on intelligence reports that Osama bin Laden's terrorist network may strike, officials said.

The information was deemed credible, said Attorney General John Ashcroft, but "unfortunately it does not contain specific information as to the type of attack or specific targets."

The FBI issued a terrorist alert on Oct. 11, saying an attack could come over a period of several days. The new warning specified a strike could come this week.

FBI Director Robert Mueller said the Oct. 11 warning may have helped avert an attack. Ashcroft said the absence of an attack should not lull people "into a false sense of indifference."

"It's important for the American people to understand that these (alerts) are to be taken seriously," said Ashcroft.

He urged Americans to "go about their lives." But the warning led him to cancel plans to travel Monday to Toronto to address a conference of police chiefs.

Officials said the warning was based in part on intelligence that Osama bin Laden's al-Qaida network may be agitating to strike again in the aftermath of the U.S.-led bombings on Afghanistan.

"There certainly is intelligence that causes you to be concerned, and possibly that al-Qaida may be behind it," one senior U.S. official, insisting on anonymity, told The Associated Press.

Ashcroft said federal agencies were beefing up security and immigration authorities were increasing their efforts to keep suspected terrorists from coming onto U.S. soil.

The alert came as investigators continued to search for the source of the anthrax that has killed three people and infected dozens of others on the East Coast.

So far scientists have not matched the anthrax mailed from New Jersey with any samples of anthrax available in the United States, a source speaking on condition of anonymity told The Associated Press.

Investigators suspect that a single person, perhaps a deranged U.S. resident with a biochemistry background, may be behind the attacks.

Officials have ruled out the presence of the additive bentonite, which could make the spores spread more easily through the air.

But the anthrax found in a letter to Senate Majority Leader Tom Daschle included silica, a crystal commonly used as a drying agent to control clumping in pharmaceuticals.

The presence of silica suggests that whoever sent the anthrax wanted it to float in the air so people would inhale it, said Greg Poland, a professor of infectious diseases at the Mayo Clinic. Poland advises the Defense Department on protecting troops against biological threats.

Law enforcement notified

Ashcroft said the FBI alert went out to 18,000 law enforcement agencies through an internal warning system.

District of Columbia executive assistant police chief Terrance Gainer said he first learned of the warning when reporters called him. "We ultimately got paged from the FBI to watch and see it on CNN," said Gainer.

An FBI spokeswoman said the warning went out to police before the news conference.

Gainer said the warning was "too amorphous" to warrant moving his department to its highest state of alert. He said D.C. police would still remain at an increased level of security.

The new warning came as jumpy Americans prepared to celebrate Halloween on Wednesday. Stories circulating on the Internet warned about possible attacks on Halloween. Justice Department spokeswoman Mindy Tucker said authorities had received no specific information about a Halloween attack.

The alert follows the enactment Friday of new anti-terrorism laws that provide prosecutors with intelligence files on suspected terrorists and give them greater surveillance powers. Tucker said the Justice Department received information about the possibility of an attack on Monday, but she wouldn't comment on whether information gleaned from intelligence files or wiretaps pointed to new attacks.

Patience urged

The attorney general asked citizens to be patient if they encountered additional security measures and to note any suspicious activities.

"We urge Americans in the course of their normal activities to remain alert and to report unusual circumstances and inappropriate behavior to the appropriate authorities," he said.

In other developments, a man whose name appears on an FBI watch list was indicted in Arizona on charges that he lied on Social Security and Federal Aviation Administration forms.

Malek Mohamed Seif, 36, was charged with three counts of making false statements and two counts of Social Security fraud, according to the indictment in U.S. District Court.