Classes were canceled Tuesday for the Los Angeles Unified School District after what the district's superintendent called a "rare" threat that comes amid new concerns about security nationwide.

An "electronic threat" received early Tuesday prompted the decision, school district police Chief Steve Zipperman said, adding that the threat "is still being analyzed."

District superintendent Ramon Cortines explained the "message" referred to backpacks and "other packages." He said many schools were threatened, though none by name. The threat was toward students in schools (as opposed to on buses).


Cortines noted the school district often receives threats. While he didn't go into detail, he said recent events -- including this month's massacre in nearby San Bernardino, California; the Paris terror attacks; and heightened concerns about potential terrorism across the United States -- as factoring into the cancellation.

"The circumstances in the neighboring San Bernardino, I think what has happened in the nation, I think what happened internationally" played into the decision, Cortines said. "I, as superintendent, am not going to take the chance with the life of students."

The superintendent said he's asked all schools to be searched thoroughly. He and school board members then will decide whether or not classes will resume Wednesday. Anyone at a school building when the notice went out around 7 a.m. PT (10 a.m. ET) Tuesday was asked to go home.

"I'm not taking a chance to bring (students into a school) until I know it is safe," Cortines said.

The school district is the second largest in the United States. During the 2011-2012 school year, it had more than 660,000 students in kindergarten through 12th grade, plus more than 250,000 in adult education programs.