TikTok said it conducted an exhaustive search of its platform and found no threats promoting violence at schools Friday. 

“What we find are videos discussing this rumor and warning others to stay safe,” TikTok said in a series of tweets.

Reports of threats made on TikTok about shooting and bomb threats at schools around the country prompted school officials in states including Arizona, Connecticut, Illinois, Montana, New Jersey, New York and Pennsylvania to increase police presence Friday. 

Some TikTok users said they planned to stay home. And at least a few districts announced plans to close school buildings, including Gilroy High School in northern California. 

Gilroy police said they had found threats on social media not to be credible, but school officials said final exams scheduled for Friday, the last day before winter break, would be postponed to January out of an abundance of caution.

"Making the decision to cancel classes tomorrow has not been an easy one," Principal Greg Kapaku said in a message to parents.

Federal and local officials sought to assure parents and students the posts were not considered credible. 

The Department of Homeland Security said Friday morning it was “aware of public reporting that suggests possible threats to schools on December 17, 2021. DHS does not have any information indicating any specific, credible threats to schools but recommends communities remain alert.”

TikTok said it was working Friday to remove “alarmist warnings that violate our misinformation policy.”

Still, the social media posts and reports about them had many educators on edge in the aftermath of last month’s shooting at Oxford High School in Michigan that left four students dead and seven people injured.

Many school districts sent messages to parents. 

"We are writing to inform you and not alarm you," Oak Park and River Forest, Illinois, school administrators said in an email to parents. "We have been made aware of a nationwide viral TikTok trend about 'school shooting and bomb threats for every school in the USA even elementary' on Friday, December 17."

Pedro Garrido, schools superintendent in Roselle Park, New Jersey, wrote in an email to parents Thursday: “Although, law enforcement is unaware of any specific, credible threats concerning these postings, the district, out of an abundance of caution, and after consulting with the Roselle Park Police Department, will take all necessary precautions to keep our students and staff safe, including additional police presence around all of our buildings.”

TikTok blamed the media for contributing to the panic and potentially inspiring real attacks. 

“Media reports have been widespread and based on rumors rather than facts, and 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 social media company tweeted.

In Dayton, Ohio, school officials said in a statement that students should be careful about the social media posts they share.

"It can be easy for students to get caught up in sharing what they see on social media, but those actions can sometimes have real-world consequences,” they said.

The post most widely associated with Friday’s fears is “not really a threat, it’s just saying they are hearing this thing is happening,” said Justin Patchin, a criminal justice professor at the University of Wisconsin-Eau Claire and co-director of the Cyberbullying Research Center.

How to respond to that presents a dilemma both to TikTok and educators, especially since many of the previous panics about TikTok challenges have proven to be bogus and acknowledging them can make them more influential.

“It definitely puts schools in a tough spot,” said Patchin, whose center has worked with TikTok and other social media companies in the past to research online bullying. “There are these potential threats they can’t ignore but they also can’t shut down schools every time someone posts a generalized threat on social media.”

The TikTok posts follow a disturbing trend that has had students acting out in response to social media challenges. In September, students across the U.S. posted videos of themselves vandalizing school bathrooms and stealing soap dispensers as part of the "devious licks" challenge.

In October, students were challenged to slap a teacher, prompting the National Education Association to call on the leaders of Facebook, Twitter and TikTok to intervene.