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

7:10 a.m.

All public schools in the Los Angeles area have been ordered closed due to a threat.

School district spokeswoman Ellen Morgan announced the closure Tuesday but released no further details ahead of a press conference at district headquarters.

The district, the second largest in the U.S., 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 (1,866 square kilometers) including Los Angeles and all or part of more than 30 smaller cities and some unincorporated areas.