LOS ANGELES (AP) — The latest on the closure of Los Angeles Unified School District schools due to a threat (all times local):

12:45 p.m.

The ranking Democrat on the House Select Committee on Intelligence says the threat that shut down the Los Angeles school system is believed to be a hoax.

U.S. Rep. Adam Schiff, D-Calif., said a preliminary investigation indicates that the threats in Los Angeles and New York City were designed to disrupt school districts in large cities.

He says in a statement Tuesday that investigators are still gathering information about the origin of the threats.

Officials have said the threats targeted students and involved gun attacks and explosive devices. It led Los Angeles school officials to close more than 900 public schools and 187 charter schools.

New York City officials say they received the same threat as Los Angeles but quickly concluded it was a hoax.

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11:30 a.m.

A threatening email sent to the New York City school superintendent warned that every school in the city would be attacked with pressure cooker bombs, nerve gas agents, machine pistols and machine guns.

The email was sent early Tuesday and said the writer and "138 comrades" would carry out the attack. It said, "The students at every school in the New York City school district will be massacred, mercilessly. And there is nothing you can do to stop it."

The anonymous writer claimed to be a student at a district high school who had been bullied.

A law enforcement official with access to the document provided the email to The Associated Press. The official wasn't authorized to disclose details of an ongoing investigation and spoke on condition of anonymity.

— From Associated Press writer Colleen Long in New York

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11:20 a.m.

The Los Angeles police chief says the emailed threat that shut down the nation's second-largest school district described an attack with assault rifles.

Chief Charlie Beck said Tuesday that it was specific to all the campuses in the Los Angeles Unified School District. He says the email's "implied threat" involved explosive devices and the "specific threat" was a shooting attack.

Beck says the email was routed through Germany but that police believe its origin was much closer.

The police chief says the city takes threats against its schools seriously given the recent attack in San Bernardino and the frequency of school shootings.

He says the LAPD gave advice to district officials, who then chose to close all of its more than 900 schools and 187 public charter schools. Beck defended that decision.

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10:45 a.m.

The White House says the different reactions taken by the nation's two largest public school systems after receiving threats show that local first-responders are responsible for protecting their communities.

Spokesman Josh Earnest says he won't "second-guess" the decisions by Los Angeles officials to close their schools and New York City officials to keep their students in class.

Earnest says local authorities make decisions based on information they receive and what they believe is in the best interests of their communities.

He says that the FBI has been in touch with California law enforcement authorities.