A group of parents in Missoula, Mont., are upset over the religious nature of Christmas songs performed at a local elementary school -- alleging the songs about Jesus are unconstitutional and a "form of bullying," Fox News reports. The parents are threatening to sue the Missoula County Public School District unless songs like "Joy to the World" and "Good Christian Men Rejoice" are replaced with secular tunes. "Bullying is such a hot topic, yet that seems to be what is occurring here," the parents, whose children attend Chief Charlo Elementary School, wrote in a letter obtained by The Missoulian. "When the children are singing about the lord and savior Jesus Christ -- public school is not the place." The school has a number of students who are Jewish, Buddhist and Muslim, and according to the parents, "one of the largest complaints last year was the young children singing about 'their Lord.'" Superintendent Alex Apostle said he took church and state issues seriously. "These are difficult waters sometimes, and I think we are moving forward in a respectful way," he said. "We as a school system want our children to enjoy the holiday season. In the process, we are obviously respectful of the beliefs and cultures of all children and their families."