Tensions at Edina High School escalated over the weekend after a Veterans Day observance sparked complaints about some students’ behavior and allegations of racism against others.

Edina Schools Superintendent John Schultz sent an e-mail to district families Monday describing a series of incidents fanned by social media and an “inflammatory and creepy” video.

“It is important that we model for our young people how to express our views and engage with each other respectfully within the safe environment of our school and online,” Schultz said.

The events apparently were triggered by an Edina High School Veterans Day assembly Thursday. About 10 students stayed seated when the national anthem was played at the event, said district spokeswoman Susan Brott.

Over the weekend, members of the Edina Youth Conservatives Club (YCC) took to the group-messaging app GroupMe to trade disparaging comments about students, which included some Somali-Americans.

A YCC member posted a video of the seated students on Twitter, which “eventually started to blow up,” said Nick Spades, the YCC president.

Spades said the students also remained seated during the playing of “Taps.” He said that both his grandfathers had served in the military, and that action got to him.

The assembly protest stirred outbursts on Twitter, as well as group chat comments from YCC members that Spades said the group does not support.

In response, a video from a YouTube user called “Antifa EHS” featured a masked and hooded speaker reading a list of demands to the Edina YCC. It called for the removal of racist students from the club and asked them to “apologize for fostering racism in your official GroupMe.”

“Meet these demands, or we will be going to the administration,” the speaker in the video said. “Consider yourselves warned.”

The district’s investigation with the Edina Police “has uncovered no credible or legal threat against EHS, or any Edina student, staff member or school,” according to Schultz’s statement.

The incident comes during a rocky fall for the Edina district after an article by the conservative think tank Center of the American Experiment charged political “indoctrination” in the schools.

Spades said the YCC met with members of the school’s black student union on Friday to talk about the protest.

But after the Antifa EHS video circulated Monday morning, Spades left school early, saying he didn’t feel safe there.

He aims for future meetings to keep “bringing us together instead of dividing us,” he said.