Students in the Gender-Sexuality Alliance (GSA) club at Olathe Northwest High School in Olathe, Kan., reported being subjected to harassment when they marched in the school's homecoming parade on Thursday. The harassment, according to a parent and several students, included chants of "Make America straight again," as well as derogatory social media posts following the parade.

"What we experienced yesterday will plague the minds of some of us forever," a statement on the Olathe GSA's Twitter account read. "We chanted louder over the hateful slurs and statements of violence that were being thrown, as well as objects actually being thrown at us."

Students in the GSA also shared screenshots of the online harassment to the club's Twitter account: "Notice how all the gays are all ugly they're like the leftovers nobody really wants," one screenshot of a Snapchat message stated.

In a statement sent to NBC News, a spokesperson for Olathe Public Schools said the incident is being investigated.

"We were incredibly disappointed to learn that during the Homecoming Parade at Olathe Northwest, students representing the Gender-Sexuality Alliance student group were subjected to harassing and derogatory comments by other students," the spokesperson stated. "The Olathe Northwest High School administration is taking this situation very seriously and is thoroughly investigating and making it very clear that derogatory language and action is absolutely not acceptable."

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Cassandra Peters is a mother of two whose son is in the GSA and was walking in the parade when the incident occurred. Peters is also the executive director for JoCo Q-Space, an LGBTQ youth center for kids 12 to 20.

"The school made an attempt to provide support from teachers and counselors to the victims of this abuse and eventually sent out a generic email about about not tolerating bullying, and that's a start, but it's not good enough," Peters said. "They may have suspended a couple of kids, but that's not enough. How can parents have these discussions with their kids when the email sent home doesn't even tell them the subject they need to talk about?"

You are so brave, we are honored to know you! Stay strong and love yourself. #standwithonw @gsa_onw pic.twitter.com/ctrGzzRRA5 — JoCo Q-Space (@JoCoQSpace) September 23, 2017

Peters, who said the "Make America straight again" chant was in response to a GSA club member wearing a "Make America gay again" shirt, is holding a solidarity rally on Tuesday at the high school.

"My goal is only to brighten their morning and give them a positive start to the day," Peters said. "What happened can cause some pretty bad fear and isolation, but we want to show them they have a huge supportive community and that those kids were nothing more than a vocal minority."

Equality Kansas, a local LGBTQ advocacy group, called on Olathe Public Schools to "take immediate action against those who participated in the bullying and harassment."

"Kids should never be bullied for being LGBT or for any reason," Thomas Witt, the organization's executive director, said. "We call on the school district to put an immediate end to this happening in the future."

David Alonzo, chair of the Greater Kansas City chapter of national LGBTQ advocacy group GLSEN, said LGBTQ allies are critical and should let themselves be known.

"Having a GSA is important," he said, but "we need to be sure allied teachers and faculty members are visible. It's great to be an ally, but if no one knows you're an ally then it doesn't go any good."

While the Olathe school district continues its investigation, its focus will be "to make sure all of our students feel safe," the district's spokesperson said. "It is our continued commitment to treat each other with respect and kindness."

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