LOS ANGELES » Heavily armed sheriff’s deputies stood watch today at a Los Angeles-area subway station named in an unconfirmed threat and Mayor Eric Garcetti took the line to work to show confidence in security measures.

Temporary barriers were in place at the entrance to the Red Line station near Universal Studios and some commuters were subjected to bag searches as deputies stood by with rifles and dogs.

The mayor, who had urged people to go about their normal routines, used the station to get to work.

Garcetti said the threat was reported to an overseas tip line and relayed to the FBI.

“So this threat did not come from a person directly,” he said. “It came from a person who said they knew of a person.”

Garcetti would not release further information, including the country where the call was received.

Information about the potential threat was relayed to the FBI’s Joint Terrorism Task Force from international partners Monday morning and was publicly revealed in a Monday night press conference.

Deirdre Fike, assistant director of the FBI’s Los Angeles office, said the credibility of the threat was still being investigated but it was announced due to its specificity and because the attack was threatened for the next day.

Area U.S. Rep. Adam Schiff, ranking Democrat on the House Intelligence Committee, said he was briefed by law enforcement about the threat.

“While the threat is still under investigation, law enforcement and local officials acted appropriately by alerting the public promptly, increasing security and urging residents to go about their normal daily business,” he said in a statement that recalled a threat that closed the Los Angeles Unified School District last December.

“If it turns out to be a hoax like the prior threat against the LAUSD, it will represent another profound example of the extraordinary cost imposed on communities throughout the United States by such actions,” Schiff added.

The Universal City Red Line station is adjacent to the studio theme park, the Universal CityWalk entertainment district, hotels and office buildings.

The line carries commuters from the San Fernando Valley to Union Station in downtown Los Angeles. About 150,000 riders a day take it and the Purple Line, which covers some of the same route.

Police Chief Charlie Beck and Sheriff Jim McDonnell said stepped-up security would include additional uniformed officers as well as officers in plainclothes.

“This could be real, it could be a hoax. But we must remain calm but vigilant,” McDonnell said.

Both he and Beck encouraged anyone who sees anything suspicious to contact authorities immediately.

AP photographer Richard Vogel and reporter John Antczak contributed to this report.