LOS ANGELES, Dec. 24 (Xinhua) -- A bomb warning led a shopping center in California's West Sacramento city to be temporarily evacuated Sunday afternoon but was then found to be a hoax call.

Police said a woman called in from the parking lot of the shopping center, saying she believed there was a bomb in her car.

A bomb squad was rushed to the scene with sniffer dogs while the lot was evacuated and the street closed. However, after searching the car and the surrounding area, police said they did not found any suspicious device.

The caller, a 49 year-old, would be taken to hospital for a mental health evaluation, police said.

The U.S. remains in a state of alert with law enforcement departments beefing up security ahead of Christmas and New Year in view of possible terrorist attacks.

Local media reported Friday that the Federal Bureau of Investigation (FBI) had foiled an attempt to blow up Pier 39, a shopping center in San Francisco.

The Los Angeles Police Department, county sheriff's department and the FBI have asked residents to remain vigilant during the holiday week.