UNIVERSAL CITY (CBSLA.com) — A warning of a possible bomb attack at the Metro Red Line subway station in Universal City was determined to be not credible, law enforcement officials said Wednesday.

Investigators also believe the anonymous caller behind the threat may have previously reported threats that did not materialize, according to LAPD officials.

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The tip – which was made from a pay phone reported to have been used to communicate bogus threats in the past – was relayed to the FBI Joint Terrorism Task Force Monday morning, authorities said.

But they also indicated the extra security measures imposed Tuesday were not immediately being totally dismantled.

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“The Los Angeles County Sheriff’s Department and Los Angeles Police Department remain on a heightened state of awareness with increased directed patrol deployments where deemed necessary,” said FBI spokeswoman Laura Eimiller.

No significant disruptions have been reported on the Metro system since authorities stepped up a police presence at the Universal City Station with barricades and a throng of sheriff’s deputies and police officers wielding high-powered weapons.

As a show of confidence to fellow Angelenos, Mayor Eric Garcetti boarded a Red Line train at the Universal City station Tuesday morning after officials first revealed the reported threat.

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