series of vague and viral tiktok posts threatening that violence will take place today. the threats are not specific to any single school, but this has prompted some districts around the country to cancel classes or ban backpacks for a day. shimon prokupecz is in new york following the story. tell us what law enforcement knows about this and also how parents should receive this. >> reporter: right. likely -- it is likely if you have a child in school today, you've received a letter or an email from the school warning you of this threat. but they're saying that it's vague, that there's no -- it's not credible. the baltimore school district tweeting saying that the police there have investigated the threat and it originated out of arizona. but nonetheless, of course, there is a lot of concern. this was a threat, a viral threat that started on tiktok. and what the new york city board of education is saying is that basically was call-in bomb threats and school shooting threats.