"I thought it was over the top," Czmowski said. "I'm all for rowdy cheering and rowdy student sections. Personal attacks, it was too much and there is no place for it."
Dave Zentner, a season ticket holder since 1955, said he didn't hear anything he considered to be offensive from the student section.
"I'm sure we've heard some dumb things over the years," he said. "I'm not sure if they were racist or bad sportsmanship. We've been road warriors and have been subjected to a lot of profanity and abuse in the league. I think overall, everybody has a few silly fans."
The reported chants followed North Dakota's return to using the Fighting Sioux nickname. The school has tried to drop the name, but supporters of the mascot recently gathered enough petition signatures to temporarily restore a state law that had required its use. The question will ultimately be put to state voters.
University of North Dakota spokesman Peter Johnson said in an email to The Associated Press that he wasn't aware of similar instances at previous University of Minnesota-Duluth games. But he said North Dakota's "name and its imagery have been used at other schools in ways that are inappropriate." He did not provide details.
Johnson said the university agrees that "inappropriate chants or cheers" have no place in college athletics and supports any "institution that works with its fans to bring some civility and focus on positive cheering."
In his letter to students, Nielson said the chants were hostile and racist.
"We decided it was an opportunity to reinforce our policy . to focus on cheering for our team and avoid comments that are considered inappropriate," Nielson told the News-Tribune.