Washington
The FBI said that it was investigating a school shooting threat on the popular social media platform TikTok as schools across the country sent alerts to parents Friday.
School districts and law enforcement downplayed the credibility of the "school shooting challenge" video which circulated on TikTok claiming there would be multiple school gun attacks and bombings around the country on Friday.
But many sent out notices to parents, as the threat came less than three weeks after the latest mass shooting in a US high school left four students dead in Oxford, Michigan.
"There is information circulating that today may be a day of attacks on schools. Administration and DC Police are very aware of this and on close watch," a message sent to parents by a school in Takoma Park in Washington said.
The Pennsbury School District in Pennsylvania told parents that there would be an increased police presence around school buildings even though they "do not believe the threat to be credible."
TikTok said it was investigating, even as it appeared to distance itself from the video that appeared on its platform.
"We handle even rumoured threats with utmost seriousness, which is why we're working with law enforcement to look into warnings about potential violence at schools," the company said in a statement.
"Even though we have not found evidence of such threats originating or spreading via TikTok," it added.
"The FBI takes all potential threats seriously. We regularly work with our law enforcement partners to determine the credibility of any threats," it said in a statement.
TikTok, one of the most popular social media services with school-aged children, has already come under fire for allowing the posting of short videos challenging people to risky, damaging and illegal acts.
Earlier this year the viral "Devious Licks" challenge video encouraged students to vandalise bathrooms at schools and make copycat TikTok videos of it.
At the time TikTok said it was taking action to remove videos and minimize their spread "to discourage such behavior."
The Everytown for Gun Safety group has tallied at least 149 school shootings so far this year, with 32 deaths and 94 injuries.
Sandy Hook Promise, a group formed in response to the 2012 mass shooting at Sandy Hook Elementary School in Newtown, Connecticut, condemned the TikTok video.
"A national TikTok challenge promotes school shootings on December 17. Gun violence is not a subject for jokes or pranks. All threats need to be taken seriously," they said in a statement.
