Students at an Alberta high school are being accused of racism and cultural insensitivity after a “Cowboys and Indians”-themed graduation party was held off campus.

Images of students from Chinook High School in Lethbridge, Alta., showed attendees wearing headdresses, war paint and feathers. Students say about 50 teenagers attended the party and shared photos of the event over Snapchat.

Many indigenous students are upset by the theme, which they say pokes fun at the brutal history of colonization and trivializes indigenous cultures.

“It’s uncalled for,” said indigenous Grade 10 student Payton Weasel Head, who said he saw pictures of students wearing Listerine bottles on their heads like headdresses.

“They were kind of making fun of our dances, our traditional dances … it was wrong.”

Some students involved apologized for the theme. In a statement, the students wrote that the event was “not intended to be a racist party, nor do the individuals that attended this event consider themselves racist.”

“The students at Chinook High are very sorry about their actions and ask for the aboriginal communities’ forgiveness.”

They added that the senior students involved “understand where individuals of the aboriginal community are coming from.” The statement also refuted allegations that Listerine bottles were worn as headdresses and said most students dressed as cowboys.

While the event was privately held, school administration called an assembly Thursday to address concerns.

“The staff and students at Chinook talked about how important it is to be publicly involved in this deep discussion of First Nations racism,” Lethbridge School District 51 said in a statement.

Payton Weasel Head’s uncle said it’s not the first time students at the school have held a “Cowboys and Indians” party. Steven Quesnelle said that when his son graduated from Chinook High School three years ago, the same theme was used.

“We’ve got to get past this. It’s old. It’s hurtful,” Quesnelle said.

With files from CTV’s Alberta Bureau Chief Janet Dirks