After receiving a credible terror threat, the Los Angeles Unified School District (LAUSD) decided to close all of its campuses as a precautionary measure. After several hours, it was detemined the threat was a hoax.

KTLA News reports school district officials as well as the police have said the school closures were due to a “credible terror threat.” An officer informed KTLA that the threat prompted the decision from LAUSD Superintendent Ramon Cortines to close all schools until further notice. More than 640,000 students ranging from preschoolers to high school seniors will not attend school.

According to the Los Angeles Times, the concern started over suspicious backpacks and packages that were left at several campuses.

The threat has prompted the authorities to execute a search operation on the over 900 schools in the district.

LAUSD Superintendent Cortines remarked that the decision to take the terror threat seriously stems from recent terror related events. “I think it’s important to take this precaution based on what has happened recently and what has happened in the past,” said Cortines.

The superintendent is no doubt referring to the shooting that took place less than two weeks ago in San Bernardino, when an ISIS-inspired couple killed 14 people in what was later labeled an act of terror.

Cortines said that he was taking no chances and immediately asked the police to search all campuses, adult school and early education centers before even thinking of reopening schools on Wednesday.

"It was not to one school, two schools or three schools, it was many schools, not specifically identified ... that's the reason I took the action that I did," Cortines said, according to Reuters.

"I am not taking the chance of taking children any place into the building until I know it's safe," he added.

According to Cortines, the threat came by way of an electronic message.

The Los Angeles Times reported the email threat was traced to an IP address in Franfurt, Germany. Despite the location, it is possible the location was "masked," to hide the true location of where the email was sent.