A suburban high school football rivalry escalated Friday after a Donald Trump-themed pep rally — complete with a sign depicting the border wall he wants to build — triggered allegations of racism.

Pictures posted to social media show students at Colleyville Heritage High School, an affluent, predominantly white school, posing with Trump-themed signs before a football game against Trinity High in Euless, a more ethnically diverse school where nearly half the students are considered economically disadvantaged.

A girl who identified herself as a Colleyville Heritage student posted photos on Twitter with the caption, "colleyville is going to TRUMP trinity tonight."

Students with a pep rally sign that depicts the "wall" Donald Trump wants to build along the Mexican border, with a message that says "paid for, by Trinity." A student who posted the photo says school administrators approved the signs. (Twitter)

Particularly troubling was the sign at the pep rally showing a wall, with the message, "paid for, by Trinity." Some interpreted that as a derogatory comment on Trinity's diverse population and an apparent reference to Trump's insistence that the Mexican people will pay to build his wall.

In response to a backlash on social media, the Colleyville Heritage student tweeted a statement saying that school administrators had approved the signs. "They had no intent of offending anyone in anyway," she wrote.

OKAY EVERYBODY BEFORE YOU @ ME PLS READ THIS pic.twitter.com/HJfi16UyPV — audrey (@audreywarnerr) September 10, 2016

Rick Hadley, spokesman for the Grapevine-Colleyville Independent School District, declined to comment Saturday on whether administrators approved the signs. He said the pep rally's theme was "Make Colleyville Great Again."

"The thinking was that if we could beat Trinity, Colleyville Heritage football would be great again," he said, adding that patriotic colors were intended to coincide with military appreciation night at Friday's football game.

He said the district is looking into what happened and hopes to use it as a "learning opportunity."

Cooper Enright, a sophomore at Colleyville Heritage, said a small group of students had a say in the posters, which do not reflect the views of the "majority of the student body."

"At the pep rally I leaned over to a friend next to me and was like, 'how was this allowed?'" he said. "Who thought it was appropriate to have our student body represented in that way?"

The pep rally created an online firestorm, drawing criticism from Trinity and Colleyville supporters alike. People condemned the rally on social media as "disgusting" and "racist" and embarrassing. The issue even drew the attention of NBA player Myles Turner, who went to Trinity.

Trinity don't y'all dare lose to Colleyville tonight in spite of this foolishness — Myles Turner (@Original_Turner) September 9, 2016

I'd just like to clarify that a pep rally theme is not a reflection or representation of the views of an entire student body 😁😁 — Nasir Panjwani (@nasirpan) September 10, 2016

I'm a Colleyville alumni and I hope trinity beats you guys https://t.co/PPj8EPtbcH — Dwight Squire (@Dwighty40) September 9, 2016

Nahil Hamam, a 2009 Trinity graduate whose Facebook post about the rally went viral, was among those upset by the signs.

In the 2014-15 academic school year, a performance report listed Trinity as 21 percent black, 26 percent Hispanic and 36 percent white, with nearly 46 percent of students categorized as "economically disadvantaged." Niche, a startup that ranks schools, named Trinity as the most diverse public high school in Texas — and No. 6 in the U.S.

"People have made snide comments before about us not being as wealthy, but nothing as far as building a fake wall," Hamam said.

She said she interpreted the pep rally signs as saying, "get out of here, basically ... 'othering' us for being diverse, stating that we don't have a claim to the American dream or we don't have a claim to the football field."

Angel Lopez, a Trinity junior of Mexican heritage, said he was furious when he saw photos from the pep rally.

"If they telling Trinity to pay for the wall, for me, it's saying we're all Mexicans — but we' re not," he said. "We have a lot of diversity."

Hadley, the Grapevine-Colleyville ISD spokesman, said the district "values all students from all backgrounds."

Jimena Ruiz, another junior at Trinity, said she and her friends were offended at first. "But then we realized, we're better than that school and we have more respect so we're going to show them," she said. "We're going to show them who we really are."

For Lopez, the best way to do that was to show up to Friday night's game and cheer on his team. And "why not?" he thought. "I'll bring a flag, too."

He said he brought a Mexican flag — and tied it together with a flag of his high school — as a symbol of unity and equality.

Meanwhile, the team on the field had its own way of dealing with an aggressive high school rivalry: Trinity stomped Colleyville Heritage 35-21.