A number of high schools were threatened on social media by a group called "Clowns in the 6," prompting Toronto police to launch an investigation.

The group reportedly mentioned eight schools in the Toronto Catholic District School Board as targets, according to TCDSB spokesperson John Yan.

On Tuesday, Yan said a number of principals contacted him to let him know about the threats.

"Students had become aware on Twitter, Instagram and Snapchat that a number of our high schools had been specifically named as targets for potential clown attacks," Yan told CTV Toronto on Wednesday afternoon.

Clown attacks -- when people dress as menacing clowns to haunt, hurt or instill fear in others -- have become popular in North America. Posts of people wearing clown costumes have surfaced on social media as well, with people documenting the strange behaviour.

"The appearance of a hit list in making the rounds through social media with specific mention of ... schools that will be attacked," Yan said in an email to parents at the schools mentioned by Clowns in the 6.

Yan said he believes there is no imminent threat to students' safety, but is working with the police as a precaution.

"Toronto Police Services has indicated that they have extra patrols in the area and they're taking the threats seriously," Yan said.

In the email to parents, Yan requested that anyone who sees a post on social media or online from "Clowns of the 6" should send it to Toronto police.

"(Parents should) just remind their son or daughter, as we always do, we're heading into shorter days. Beware of your surroundings and all the normal safety messages about travelling with a friend," he said.

Around 3 p.m. on Wednesday afternoon, there was a clown sighting at a school near College Street and Ossington Avenue. A parent, who wanted to remain anonymous, told CP24 that a clown chased around children.

There were no injuries, but the parent said some children were crying and afraid.

Toronto police Sgt. Scott Villers confirmed that two 15 year olds, one dressed as a clown, were filming a video for YouTube.

Villers said they were under investigation and it was later revealed they would not be charged.

It was not immediately clear if there was a connection between the clown spotted at the school Wednesday afternoon and the threats made against schools in the TCDSB.

Police have requested that any principals who may have received threats to contact them to file a formal report so officers can investigate further.