Los Angeles metro system bomb threat not credible: FBI

LOS ANGELES (Reuters) - A threat to detonate a bomb at a subway station in Los Angeles was not credible, federal authorities said late on Tuesday after police spent the day searching commuters and leading bomb-sniffing dogs around stations across the metro area.

Authorities found no evidence regarding a specific but uncorroborated threat made by a caller who warned that a bomb would blow up on Tuesday at the Metro Red Line's Universal City station, the Federal Bureau of Investigation said.

"Based on significant similarities, law enforcement partners also believe the anonymous caller may have, on a previous occasion, reported threats that did not materialize," the FBI said in a statement.

Heavy security at subway stations in Los Angeles greeted commuters on Tuesday. Armed deputies searched passengers' bags while bomb squad teams led dogs around stations across the Los Angeles County transit system, media footage showed.

Los Angeles Mayor Eric Garcetti, who boarded a train at the Universal City station on Tuesday, said law enforcement was prepared and asked the public to be vigilant.

Federal and city officials said on Monday they had been alerted by authorities in another country to a "specific" threat against the city's Red Line commuter rail system, prompting them to beef up security and alert the public.

Law enforcement officials said the threat had been relayed to the FBI by a law enforcement agency in another country, where the threat had originated. Officials did not identify the country.

The male caller, speaking in English, had warned authorities in that country of a potential attack on Tuesday targeting the Red Line station, which is across the street from the Universal Studios theme park, Los Angeles Police Chief Charlie Beck said.

The caller did not threaten to carry out the attack, but said he was alerting law enforcement.

The Red Line runs between downtown Los Angeles and northern neighborhoods, including Hollywood and North Hollywood. It carries about 145,000 passengers a day as part of the city's larger transit system.

(Writing by Gina Cherelus in New York; Additional reporting by Gina Cherelus in New York and Brendan O'Brien in Milwaukee; Editing by Daniel Wallis, David Gregorio and Paul Tait)