May 20 (Bloomberg) -- The Federal Bureau of Investigation warned law enforcement agencies to be on the watch for suicide bombers who may strike within the U.S., Time magazine reported in its on-line edition, citing unidentified FBI sources.

A lightly classified intelligence bulletin headlined ``Possible suicide bomber indicators'' was sent electronically to 18,000 law enforcement agencies Thursday warning police to look out for people wearing heavy, bulky jackets on warm days, smelling of chemicals, trailing wires from their jackets or tightly clenching their fists to hide a detonator, the Times reported.

The warnings were prompted by renewed concern that extremists opposing the U.S. occupation of Iraq or support for Israel could launch attacks here, Time said, citing FBI sources. There's no hard intelligence warning of specific attacks by suicide bombers, the magazine said.

Joe Parris, a spokesman for the FBI in Washington, told Bloomberg News that a bulletin not intended for public dissemination had been distributed to law enforcement agencies and declined to say what the bulletin was about.

The bulletin contained ``uncorroborated intelligence'' which can ``unduly concern the public,'' Parris said.

``They are general background things that law enforcement might want to be on the look out for,'' he said.

(Time.com, 5-21)

Click Time.com for Time's Web site.

To contact the reporter on this story: Karen Gullo in San Francisco at kgullo@bloomberg.net.

Last Updated: May 20, 2004 21:48 EDT