FBI discounts terror threat to US bridges

The FBI has discredited the raw intelligence behind last week’s warning that terrorists might attack West Coast bridges.

However the agency wants police to remain on high alert and guard against possible terrorist activities in the United States and abroad, officials said.

The FBI received uncorroborated intelligence last week suggesting terrorists might strike suspension bridges on the West Coast between last Friday and Wednesday and issued a private warning in eight states.

The warning also went to many companies in the region through the FBI’s Infragard network that alerts industry to threats.

California Governor Gray Davis then made the information public, suggesting officials had ‘‘credible evidence’’ of a possible terror attack on four bridges in his state.

National Guard troops took up positions on the bridges, and transportation officials beefed up security from the Golden Gate Bridge in San Francisco to the Holland Tunnel in New York.

But agents who looked further into the raw intelligence found no evidence to corroborate the threat, officials said. They issued an updated message to police yesterday.

‘‘Recipients should be advised that FBI investigation has determined that the threat to suspension bridges is not deemed credible,’’ the message said.

The reassessment came as a top FBI official acknowledged agents still have few clues in the investigation into anthrax attacks that have left four dead and made 13 more Americans ill.

FBI counter-terrorism official James Caruso has told a Senate Judiciary subcommittee hearing federal law enforcement officials still did not know how many US labs that handled anthrax or other biological agents.

‘‘We do not know that,’’ Caruso said. ‘‘We are pressing hard to determine. I know it’s an unsatisfactory answer and unsatisfactory to us as well.’’