On a day where Edmontonians took to the streets to celebrate Pride, a colourful flag raised at a southwest Edmonton high school was cut down and replaced by a regular Canadian flag.

Trish Horobec saw the flag, raised at the Lillian Osborne School Friday in Terwillegar, was missing Saturday afternoon and posted a photo to Facebook.

"As you can clearly see from the photo, it was physically cut from the flagpole and removed," she wrote.

Trish Horobec posted a picture of the cut-down flag to a Facebook group Saturday. (Facebook)

She also reported it to the Edmonton Police Service.

The report of the cut-down flag comes on the same day as Edmonton's 37th Pride parade, which aims to celebrate inclusiveness and the acceptance of the LGBTQ community.

Flag was up for less than a day

​Horobec said she saw the flag was up in a Facebook post Friday. She went to see it for herself Saturday and saw it was cut down.

"It's really horrible to vandalize property in general, but in particular vandalizing the Pride flag, on Pride day, is just not done," she said Saturday. "That's awful."

Tirsh Horobec said she expects kids in the gay-straight alliance at the school may be devastated, but encourages them not to be. (Zoe Todd/CBC)

She said she saw in Facebook comments of the original post some students were upset about the flag replacing the Canadian flag for one week. The flag was raised for one week with the approval of the school.

Horobec said the fact the flag was cut down sends a clear message to LGBTQ students and their allies. "Somebody came out here and said, 'no, you don't belong,' " she said. "That's not a message that anybody should be cool with."

Purpose not clear: principal

Janet Hancock, the principal of Lillian Osborne School, said it wasn't clear to her what the motive behind the missing flag was. "It's very difficult to know if this is an attack on any particular group until we find out more about it," she said, adding it wasn't clear to her if the person who removed the flag meant any harm.

Hancock said she gauges how upset her students are by emails she receives. When she spoke to CBC on Saturday afternoon, she had received none.

"I think it will be kind of an, overall, a mild event," she said. "It could be definitely disappointing and we'll find out more about it once we find out the reason behind it."

Remnants of the previous flag flank the Canadian flag raised Saturday. (Zoe Todd/CBC)

Lillian Osborne school has a gay-straight alliance, and she said many students from the high school attended the Pride parade Saturday.

She said she will gauge the mood of her students and staff on Monday before taking further action.

"I'll really be focusing on our kids and our culture," she said.

'Pretty devastating impact'

Horobec said whoever cut down the flag needs to send their message in a different way.

"In future, disputes need to be settled through proper channels, not by scaling the flagpole with a knife," she said.

She said she expects the LGBTQ community and their allies to be affected by the vandalism, but hopes the community knows it's supported by others.

"This going to have a pretty devastating impact, I would expect, for the students in the gay and straight alliance at this school," she said.

"Please, don't let this devastate you and don't let it bring you down. This is the actions of one person. It is not representative of how we all feel."

Flag will return

Bob Turner, the MLA for Edmonton-Whitemud, tweeted Saturday he will replace the flag as soon as possible.

Really sorry to hear this. Please let the student know I would be honoured to pay for a replacement flag asap. <a href="https://twitter.com/Lillian_Osborne">@Lillian_Osborne</a> <a href="https://twitter.com/hashtag/Pride2017?src=hash">#Pride2017</a> <a href="https://t.co/1rnVKgAlpW">https://t.co/1rnVKgAlpW</a> —@DoctorCanBob

Turner said he was disappointed when he caught wind of the flag being cut down. "I thought it was really a shame, actually," he said Saturday.

He said it's unclear if the person was even from the neighbourhood, which he represents provincially and described as having "tremendous community spirit."

Wanting to replace the flag, Turner said everyone involved — including the Edmonton Public School Board and the Edmonton Pride Festival — were quick to respond.

"Everybody's pulling together on this," he said, with the new Pride flag expected to go up Monday sitting on his table.

"I'm just the guy that picked up the flag."