Public schools in Los Angeles are to reopen on Wednesday after a terror threat authorities now believe to be a hoax.
More than 1,000 schools were closed after an email was sent to a school board member.
Hundreds of thousands of schoolchildren were sent home after a threatened attack "with bombs and assault rifles".
The email was routed through Germany but it is thought it originated locally.
The threat that led to the closure of all public schools in Los Angeles is most likely a hoax, federal officials said.
The officials, who asked not to be named, echoed an assessment by New York Police Commissioner William Bratton that the decision Los Angeles authorities took to shut the school system was an over reaction.
US Congressman Adam Schiff, the top Democrat on the House Intelligence Committee, later said that a preliminary assessment suggests the emailed threats to New York and Los Angeles school districts were a hoax.
The Democratic presidential candidate may also have shown his cards on his choice of running mate.
The US president also shared a post on Twitter accusing Dr Anthony Fauci of misleading the public over hydroxychloroquine.
Fears over an impending second wave of coronavirus dominates Wednesday’s front pages.