The US city of Los Angeles ordered all public schools closed Tuesday due to a “credible” electronic threat targeting the district and its 640,000 students.
Ramon Cortines, the superintendent of Los Angeles schools, said he ordered the shutdown after police alerted him to a threat “made not to one school, two schools or three schools. It was many schools.”
Cortines said the threat made mention of backpacks and “other packages.”
The Los Angeles Unified School District tweeted: “LAUSD schools are closed today due to credible threat.”
Police and FBI agents were called in to help search the more than 1,000 schools in the district, Cortines told a news conference, adding that he expected the operation to be completed by the end of the day.
The superintendant said the extraordinary measure was triggered in part by the December 2 attacks that killed 14 people in nearby San Bernardino.
“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.
The chief of the Los Angeles school police department, Steven Zipperman, also stressed the decision was an extreme precautionary measure.
“Earlier this morning we did receive an electronic threat that mentions the safety of our schools,” he told the news conference.
“In an abundance of caution, as the superintendent has indicated, we have chosen to close our schools today until we can be absolutely sure that our campuses are safe.”
Zipperman said that private schools in the district had remained open since the threat was only directed at the LAUSD.
The news conference was held shortly after 7 am local time, before the start of the school day for most children.
Steve Zimmer, president of the Los Angeles school board, said those families whose children had already been dropped off had been contacted and asked to come and collect them.
The LAUSD is the second largest education district in the nation with more than 900 schools. The district comprises more than 21,000 buildings spread over 720 square miles within Los Angeles and nearby communities.
California has been stunned by the massacre in San Bernardino, carried out by US-born Syed Farook and his Pakistani wife Tashfeen Malik.
Authorities believe the Muslim couple had been radicalized for some time and may have been inspired by the extremist Islamic State group.
The couple were killed in a shootout with police following the massacre, which the FBI is treating as an act of terrorism.