Students are being warned to keep their eye out for people dressed like clowns around school property after a frightening incident in Toronto’s Trinity Bellwoods neighbourhood Wednesday.

Children who attend a school in the Dundas Street West and Ossington Avenue area were walking outside their school when someone dressed in a scary clown costume started running towards them. A second person stood back filming the incident.

The two young students told a teacher and a parent, all of whom promptly reported the incident to 911.

The principal of Pope Francis Catholic School, Joanne Saragosa, told reporters Thursday that she and two parents immediately went outside to try and track down the culprits.

Two 15-year-old males were detained and questioned by police but they were released with just a warning.

Saragosa said the incident turned out to be “some sort of prank.”

“Kids of a certain age get ideas and they’re not always thoughtful of how they follow through,” she said.

There have been an increasing number of incidents in both the U.S. and Canada where people dressed as scary clowns have taken to the street with the purpose of taunting, harassing and instilling fear on members of the public.

Toronto police are investigating recent online threats made against eight high schools in the Toronto Catholic District School Board. The threats were made by a group calling themselves "Clowns in the 6."

TCDSB Spokesperson John Yan told CTV Toronto Wednesday that a number of principals contacted him about the threat.

"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," he said.

Yan said he believes there is no imminent threat to students' safety but that school officials are 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.

In the meantime, Yan said Thursday that schools are undertaking an educational program with older students about the dangers of pranking and scaring their younger cohorts.

“It is never cool, and it’s not funny,” he said.

For now, Yan said schools are not banning Halloween costumes or clown costumes from classroom Halloween parties.

“It’s not the costume that is a problem but the behavior behind it, the actions you do with the costume on,” he said.