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

Police say the schools were closed out of an abundance of caution.

The threat is described as a “rare threat.”

The police chief says the FBI has been notified of threat to school and that the threat stil being analyzed.

The threat was an electronic threat to the safety of the schools.

The threat was to “many schools,” the school system’s superintendent says.

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.