Los Angeles (AFP) - Los Angeles schools were due to reopen on Wednesday after authorities determined that an emailed threat prompting the shutdown of the second-largest school district in the United States was not deemed credible.
The drastic decision on Tuesday to close more than 900 schools and to keep 640,000 students at home was made out of "an abundance of caution," and in light of the deadly December 2 attacks in nearby San Bernardino, said schools superintendent Ramon Cortines.
"I'm not going to take the chance with the life of a student," said Cortines, who runs the Los Angeles Unified School District (LAUSD).
But Los Angeles Mayor Eric Garcetti told reporters later Tuesday: "We can now announce the FBI has determined this was not a credible threat."
The LAUSD said on Twitter that classes and after-school activities would resume Wednesday, adding: "When it comes to the well-being of our children, we will never take chances."
A similar threat was also made against New York schools, but officials there said they deemed it not credible from the onset and accused Los Angeles school officials of badly overreacting.
California congressman Adam Schiff said the emails, sent late on Monday from an IP address in Frankfurt, Germany, were likely a prank.
"Preliminary assessment is it was a hoax to disrupt school districts in large cities," Schiff said on Twitter.
But Garcetti cautioned it was too early to draw conclusions.
"Whether it's criminal mischief, whether it's somebody testing vulnerabilities of multiple cities, we still do not know enough to say definitively," he said.
Authorities raised the alarm after several members of the LA school board reported receiving emails threatening violence involving backpacks and packages left at some schools.
California congressman Brad Sherman told CNN that the emails had come from a person claiming to be a "extremist Muslim" who said attacks would take place on Tuesday and would involve nerve gas.
The message also said the person boasted of having "32 accomplices... all ready to take action today," Sherman said.
But in biting criticism, New York Police Commissioner Bill Bratton said the schools shutdown in Los Angeles was "totally, totally uncalled for."
"It's what they want, whether it's a prankster or a terrorist, they want to instill fear," Bratton told reporters.
Bratton, who previously served as Los Angeles police chief from 2002 to 2009, said the person behind the threat may have been inspired by the hit television series "Homeland."
New York Mayor Bill de Blasio told a press conference that the threat was "so generic and outlandish" that it could not be taken seriously.
- 'Easy to criticize' -
Bratton's comments prompted a rebuke by the Los Angeles police chief Charlie Beck, who insisted the school shutdown was justified.
"It's very easy in hindsight to criticize a decision based on results that the decider could have never known," he said.
The Los Angeles Unified School District comprises more than 21,000 buildings spread over 720 square miles (1,865 square kilometers) within Los Angeles and nearby communities.
California has been stunned by the massacre in San Bernardino, located about an hour east of Los Angeles, carried out by US-born Syed Farook and his Pakistani wife Tashfeen Malik.
The Muslim couple were killed in a shootout with police following the attack, which the Federal Bureau of Investigation is treating as an act of terrorism.
According to a new Wall Street Journal/NBC News poll released on Monday, national security has become the top issue of concern for Americans in the wake of the San Bernardino assault and last month's recent deadly attacks in Paris.