Los Angeles has closed down all of its public schools over what was described by officials as an "electronic threat."
During a press conference, school Superintendent Ramon Cortines said the system had received a threat that talked about "backpacks, talked about other packages."
Cortines said he ordered plant managers to "walk the schools" and report "anything out of order" to police.
"I think it is important that I take the precaution based on what has happened recently and what has happened in the past," Cortines said. "Before the day is over, I want every school searched to make sure that it is safe for children and safe for staff to be there on Wednesday."
Of course, the Los Angeles metro area is still reeling from a terrorist attack in San Bernardino that left 14 people dead.
Cortines would not elaborate on the nature of the threat, but parents received a recorded message from the Los Angeles Unified School District that cited a "credible terrorist threat."
Steven Zipperman, the chief of the Los Angeles School Police Department, said the department received an "electronic threat that mentioned the safety of our schools."
Zipperman said the FBI had been notified, and at the moment the "threat is still being analyzed."
The LA Unified School District serves 640,000 students in more than 1,000 schools and public charter schools.
Update at 1:16 p.m. ET. 'Could Not Take The Chance'
Los Angeles government officials — including the school chief and the mayor — defended the decision to close schools today.
"I could not take the chance," Superintendent Ramon Cortines said.
Mayor Eric Garcetti said that while he did not make the decision to close the schools, he supported the school system's decision.
"An abundance of caution is something that all of us who have children appreciate," Garcetti said.
Without naming New York City officials, Los Angeles Police Chief Charlie Beck said that it was "irresponsible to criticize the decisions" without first knowing all the facts.
Update at 11:52 a.m. ET. New York Also Received A Threat:
New York City schools also received a threat this morning, but Police Commissioner William Bratton said it was not a credible terrorist threat.
"We are very comfortable that this is not a credible threat," Bratton said, and they are "concerned with people overreacting to it."
Bratton added that these kinds of threats are "made to promote fear."
Mayor Bill DeBlasio said the threat was "so generic so outlandish and posed to numerous school systems simultaneously, there were wording choices and other indicators that suggested a hoax and not anything that we could associate with Jihadist activities."