NEWARK, Del. —  A group called “Athletes United in Christ” sparked parent complaints at a Delaware high school assembly when it tried to promote a religious concert.

The presentation at Newark High School in Newark, Del., was held with the purpose of encouraging students to make the right choices in life.

Two parents complained about the Christian group, which handed out fliers about the concert and displayed its logo, which has the word "Christ" and a cross on it. The school immediately apologized, with the principal saying “Athletes United in Christ” crossed the line.

"Parents found that offensive, and we certainly apologized for that. I apologize for that. But I do not apologize for the message," said Newark High Principal Emmanuel Caulk.

That message came from Philadelphia Eagles football player Tra Thomas, who founded the organization. Those familiar with the speech he made say he didn’t talk about Christianity.

But the Delaware ACLU calls the presentation another attempt to work religion into public schools.

Click in the video box near the top of the story to watch a full report by FOX News' Todd Connor.