A middle school teacher in Louisville has been removed from the classroom after burning two American flags in class as part of a civics lesson.

Dan Holden, a seventh-grade social studies teacher at Stuart Middle School, burned two flags Friday as part of a lesson on freedom of speech, said Jefferson County schools spokeswoman Lauren Roberts said.

The students were asked to write an opinion paper on the flag burning, Roberts said.

Holden, a teacher in the school district since 1979, has been reassigned to non-instructional duties while the incident is under investigation.

Roberts said the flag burning did not appear to be politically motivated, based on an interview with Holden.

The district also alerted city fire officials.

"Certainly we're concerned about the safety aspect," Roberts said, along with "the judgment of using that type of demonstration in a class."

Pat Summers, whose daughter was in Holden's class, told The Courier-Journal of Louisville that more than 20 parents showed up at the school Monday, upset over the incident. Click here to read the Courier-Journal story.

"She said, 'Our teacher burned a flag.' I'm like, 'What?"' Summers said.

Brent McKim, president of the Jefferson County Teachers Association, said Holden has "been teaching for many years, and has by all accounts a good teaching record. It was not a political statement and was meant to illustrate a controversial issue. To fire someone because of that would be inappropriate," he said. "It wasn't like he was taking one side or another."

An attempt to pass a constitutional amendment prohibiting flag burning failed in the U.S. Senate earlier this year.

Beth Wilson, director of Kentucky's American Civil Liberties Union, said the school district is allowed to decide what's instructionally appropriate.

But "if a school is masking their objections to flag burning under the guise of safety, it raises questions about freedom of speech and academic freedom," she said. She said the ACLU would monitor the case but is not involved at this point.

Stuart sixth-grader Kelsey Adwell, 11, said students were abuzz about the incident on Monday.

"They just can't believe that a teacher would do that — burn two American flags in front of the class," she said. "A teacher shouldn't do that, even though it was an example."