THREAT TO STATE'S BRIDGES GOVERNOR CITES 'CREDIBLE EVIDENCE' OF POSSIBLE ATTACK.

Byline: Staff and Wire Services

Gov. Gray Davis warned Thursday that law enforcement officials have what he called ``credible evidence'' that terrorists may be targeting four California bridges, including the Golden Gate Bridge, in the next six days.

Davis' decision to go public with the warning prompted the FBI to confirm information intended only to alert law enforcement agencies but to downplay its significance by noting that the threat was ``uncorroborated.''

Mayor James Hahn also emphasized that the FBI ``had not verified the information'' and that extensive security measures are in place at hundreds of locations in Los Angeles.

``Everyone should be cautious and alert, but they should also go on with their lives,'' Hahn said.

The bridges identified by Davis as possible targets were the Golden Gate and Bay Bridge, both in San Francisco, the Vincent Thomas Bridge at the Port of Los Angeles, and the San Diego-Coronado Bridge.

``The best preparation is to let terrorists know: We know what you're up to; we're ready for you,'' Davis said in Los Angeles during an afternoon news conference at which he also appointed George Vinson, a 23-year veteran of the FBI, as the state's new terrorism security czar.

Security around the bridges, heightened soon after the Sept. 11 terrorist attacks, was being further bolstered by measures that include posting National Guard troops at both ends of each bridge, the governor said.

In an interview on ``Larry King Live'' on CNN on Thursday night, Davis defended his comments: ``You have to err on the side of caution. You have to do everything you can to protect people.''

After Davis went public, the FBI publicly issued its alert, dated Wednesday, which says six ``incidents'' were planned during rush hour between today and Thursday.

``Reportedly, unspecified groups are targeting suspension bridges on the West Coast,'' says the memo issued to law enforcement agencies in eight Western states.

``We are working to verify the validity'' of the information, Justice Department spokeswoman Mindy Tucker said in Washington. She said the information that prompted Thursday's warning was still ``at a lower level'' of reliability than the information that led to the FBI's alert Monday.

National Homeland Security Director Tom Ridge said he would not second-guess the move by Davis, although federal authorities had not publicly released information about the threats before Davis did.

``I respect the decision Gov. Davis made. He exercised his judgment,'' Ridge said. ``Had he chosen not to reveal (the threats), I would have respected that as well.''

Hahn said extra surveillance already is in place for the Vincent Thomas Bridge and 300 other locations considered potential targets in Los Angeles.

``We already had extra surveillance on our bridges and freeway overpasses as well as at (motion picture) studios, television studios, government buildings and religious institutions,'' Hahn said. ``We will continue the same level of surveillance we had before, with help from the state now.''

Although hundreds of bomb threats have been called in to authorities about sites in California, this is only the second threat judged to be credible since the Sept. 11 attacks, Davis said. The first targeted Los Angeles movie studios.

Several Hollywood studios halted tours and increased armed patrols after a general warning Sept. 20 from the FBI that television and movie facilities could be targets of terrorist attacks.

In a telephone conference shortly after the disclosure by Davis, California Highway Patrol Commissioner Spike Helmick stressed that the public shouldn't be fearful.

``Those bridges are safe. We encourage people to use them. In fact, I'll be driving over them tomorrow on several occasions,'' Helmick said.

``I can't guarantee'' that nothing will happen, he said. ``I couldn't do that before Sept. 11.''

Given the absence of any searches or security checks, Helmick would not say how the soldiers and officers would be able to stop a car or a truck laden with explosives from driving onto a suspension bridge and detonating during rush hour.

Instead, he emphasized that CHP officers, with the backing of the National Guard, would be ready should anyone attempt an attack.

Officials representing the agencies that operate the bridges said they were taking the threats seriously.

``We feel we're well prepared for any nefarious and criminal actions,'' said Jeff Weiss, spokesman for the San Francisco-Oakland Bay Bridge. ``We're routinely inspecting the IDs of workers ... on the bridge to assure that everyone who is on the bridge belongs on the bridge.''

Heightened security measures include an increased presence by CHP officers, California Department of Transportation officials and U.S. Coast Guard boats patrolling the bridges, piers, catwalks and the water beneath the bridges.

Davis said terrorists planned to ``blow up'' one of the bridges, but Helmick said the threat was not that specific.

In Los Angeles, Sheila Gonzales, a spokeswoman for the Port of Los Angeles, said officials were working with police agencies to secure the Vincent Thomas Bridge. The combined ports of Los Angeles and Long Beach are the busiest port complex in the nation.

In San Diego, CHP Officer Mark Gregg said his agency has been working with the Navy, Coast Guard and local police to protect the Coronado bridge since the Sept. 11 terror attacks.

``We take any potential threat very seriously, and we adjust our methods of patrol and security accordingly, but we already had been on a strong sense of alert since Sept. 11,'' Gregg said.

POSSIBLE TARGETS

The four California bridges identified by Gov. Gray Davis as possible terrorist targets:

--Golden Gate Bridge: A 4,200-foot-long suspension span across the Golden Gate Strait at the entrance to San Francisco Bay. It carries some 110,000 vehicles per day and has had more than 1.6 billion vehicle crossings since it opened in 1937.

--San Francisco-Oakland Bay Bridge: Carries Interstate 80 between San Francisco and Alameda counties. The 4 1/2-mile length incorporates suspension, cantilever and truss, and tunnel structures. It carries some 270,000 vehicles daily.

--Vincent Thomas Bridge: Crossing over Los Angeles Harbor's main channel, it is a 6,062-foot-long suspension bridge carrying four-lane State Route 47 between Terminal Island and San Pedro. Its deck clears the channel by 185 feet. It carries an average of 39,000 vehicles per day.

--San Diego-Coronado Bridge: Spans 11,179 feet in an arc across San Diego Bay to Coronado Island, clearing the water by 200 feet. It links downtown with the affluent community of Coronado and handles 69,000 vehicles each day. The ``island'' is actually a peninsula that is home to North Island Naval Air Station, part of the largest aerospace-industrial complex in the Navy. The Naval Air Station includes Naval Amphibious Base Coronado, which is the West Coast focal point for special and expeditionary warfare training and operations.

CAPTION(S):

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Officer Rob Nelson watches the Golden Gate Bridge.

Penni Gladstone/The Chronicle

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POSSIBLE TARGETS (see text)