All schools in the vast Los Angeles Unified School District have been ordered closed due to a threat.

School district spokeswoman Ellen Morgan announced the closure on Tuesday but released no further details.

At a press conference, school superintendent Ramon Cortines said that the threat was “not to one school, two school or three schools” but to “many schools” and “at school students” generally. He declined to describe the nature of the threat.

The district, the second largest in the nation, has 640,000 students in kindergarten through 12th grade and more than 900 schools and 187 public charter schools.

The district spans 720 square miles including Los Angeles and all or part of more than 30 smaller cities and some unincorporated areas.

Courtesy The Guardian