UPDATE 5:06 p.m.: U.S. Rep. Adam Schiff (D-Calif.) said that a preliminary investigation has found that the threat which shut down Los Angeles area schools, as well as a similar threat issued in New York, was determined to be a hoax designed to disrupt school districts in large cities, according to ABC News.  

UPDATE 2:07 p.m.: Law enforcement sources have revealed that the email threat which prompted all Los Angeles Unified School District schools to close mentioned explosive devices, assault rifles and pistols, reported the Los Angeles Times. Authorities later traced the source of the threat and found it was sent from a device with an IP address located in Frankfurt, Germany. 

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All Los Angeles Unified School District schools were closed Tuesday morning after a LAUSD board member received a "credible terror threat," police said.

It remains unclear when the threat was made or who it was sent to, but police didn't take any chances, prompting them to close down all schools in the area effective immediately, according to the Los Angeles Times.

Details were sparse at a press conference where officials discussed the closures, with LAUSD Superintendent Ramon Cortines simply saying the threat was made to "students at the school," later adding that "it was a message."

The schools were all evacuated, and the students were immediately sent home, reported NBC's Southern California affiliate KNBC. Furthermore, any parents who hadn't sent their child to school yet were informed of the situation and told to keep their child home.

"The actions that we are taking today are swift and they are appropriate ... The education of our kids is incredibly important. The only thing that's more important is their safety," said Steve Zimmer, the president of the LAUSD school board.

In the meantime, police have begun to search the area for anything suspicious and will continue to do so throughout the day, reported Business Insider. Additionally, the FBI has been made aware of the situation, but it's unclear what actions it's taking.

The threat comes less than two weeks after the terrorist attack in San Bernardino, Calif., which left 14 people dead and 22 injured. As it turns out, this is part of the reason why LAUSD took the precaution to close all 900 schools in the area.

"I, as superintendent, am not going to take chances with the life of the student," Cortines said.