CNN Business  — 

A vague and viral TikTok trend warning of nationwide school violence on Friday — which authorities have dismissed as not credible — has nevertheless prompted widespread school closures, stretched law enforcement resources and put families on edge ahead of a critical holiday travel season.

A number of school districts in states ranging from Minnesota to Texas announced they were shutting down schools on Friday in response to a wave of videos, some mentioning specific schools, suggesting that students avoid coming to class on Dec. 17. In other areas, law enforcement were on high alert, sending officers to guard schools as a precaution.

The US Department of Homeland Security said Friday morning it has no evidence to suggest the claims are credible but encouraged the public to “remain alert.”

On Friday afternoon, TikTok said it had begun removing the warnings from its platform as misinformation.

“We’ve exhaustively searched for content that promotes violence at schools today, but have still found nothing. What we find are videos discussing this rumor and warning others to stay safe,” the company said in a tweet. “Local authorities, the FBI, and DHS have confirmed there’s no credible threat, so we’re working to remove alarmist warnings that violate our misinformation policy. If we did find promotion of violence on our platform, we’d remove and report it to law enforcement.”

TikTok first indicated it was aware of the warnings on Thursday afternoon, saying then that it treats “even rumored threats with utmost seriousness.”

TikTok said Friday it continues to monitor its platform for suspicious activity, but added that media coverage characterizing the viral trend as a threat of school violence could unintentionally encourage someone who may be predisposed to act — creating the very risks that families fear.

“We are deeply concerned that the proliferation of local media reports on an alleged trend that has not been found on the platform could end up inspiring real world harm,” the company said.

A federal law enforcement source agreed, telling CNN that authorities worry most that the rapidly unfolding social media narrative could drive a lone offender to carry out an actual attack. The situation is an illustration of the current threat environment in the United States, the source added.

“This is an illustration of how social media and other communication platforms play a role in spreading threat related narratives, which then can result in the need for escalated security measures in and around parts our critical infrastructure,” the source said.

Little Falls Community Schools in Minnesota said Thursday that it would preemptively close on Friday after the district was “specifically identified in a TikTok post” linked to the warning trend. Kaufman High School in Texas also canceled classes, according to a local media report. In Georgia, Atlanta Public Schools said in a letter to parents that some facilities would be beefing up security on Friday, according to local reports, while schools in Polk County closed altogether.

And in a letter posted to its Facebook page, Albemarle County Public Schools near Charlottesville, Va. said the TikTok trend is a reminder not to share posts about school violence.

“Even if they are not credible threats, they can cause a great deal of stress and anxiety for our students, families, and staff,” the letter read. “Creating or sharing such posts can also lead to criminal charges. We ask our families to monitor their children’s social media activity and speak with them about proper behavior online.”

While many of the warnings of potential violence appear to be circulating on TikTok, it is not the only platform to see such chatter in recent days. A similar message has appeared on Snapchat, according to a notice to parents by school officials in Ramsey, New Jersey. A letter by New York City officials referred to similar content on “other social media” besides TikTok.

A Snap spokesperson said the platform is closely monitoring the situation on TikTok but did not immediately provide further comment. A spokesperson for Meta, Facebook’s parent company, didn’t immediately respond to a request for comment.

The social media rumors come amid a wave of talk about so-called “challenges” on TikTok purportedly encouraging students to engage in misconduct at school. Earlier this fall, school officials in Arlington, Va. issued warnings about TikTok content that they said dared students to destroy school property and to assault teachers, according to one teacher at Arlington Public Schools who spoke on condition of anonymity because they were not authorized to speak to the press. Such warnings often come without evidence that the content being described actually exists as fact rather than legend.

NYC Department of Education Chancellor Meisha Porter addressed the issue of social media challenges in an email to families on Friday, saying that rumors of potential bomb threats or shooting threats were not specific to only New York City and many of the posts are general and not specific to one school.

“Any social media posts of challenges involving threats or actions of violence against school communities will not be tolerated,” Porter’s email said. “Threats of violence have very real consequences regardless of the reason the threat was made, and we do not want our young people to jeopardize their bright futures over social media challenges such as these.”

Porter encouraged families who see threats aimed at specific schools to call 911.

The pattern goes beyond social media. On Thursday, authorities in Franklin, New Jersey charged a 13-year-old student with creating a false alarm after the student allegedly sent a text message threatening violence at school earlier in the week. An investigation concluded that the text message was part of a prank. But one local parent, who requested anonymity to safeguard their child’s privacy, said officials’ efforts to reassure the public about non-credible threats was itself counterproductive.

“By repeatedly saying schools will continue regular schedule, it is giving the wrong message to whoever is sick enough to do something,” the parent said. “Our kids are growing up in a time when lockdowns are a normal part of their school life — but this week has added a stress that no parent should have to experience.”

The flurry of school closures has not escaped the attention of the Biden administration. On Friday afternoon, White House Press Secretary Jen Psaki said the US government is “closely monitoring” the situation.

“Today is another reminder of how many kids and parents live in fear of school shootings or violence. It is unacceptable,” Psaki tweeted.

Sonia Moghe contributed to this story