Christians are up in arms against what they perceive to be a radical and sudden transformation of the American public school system where Christianity is being eased out of children's education and replaced with Islamic "indoctrination."

In its latest report, the American Center for Law and Justice (ACLJ) said students in US public schools are now being forced to learn how to convert to Islam and recite "Allah is the only God."

"It's Islamic indoctrination right here in our schools," the organisation said.

Several concerned parents in Tennessee and other parts of the county have been in touch with ACLJ and raised concerns over the things their children are being taught in school. Brandee Porterfield, one of the parents, told Fox News that her seventh grade daughter is learning about Islam as part of world history in her class at the Spring Hill Middle School in Maury County, Tennessee.

"They did this assignment where they wrote out the Five Pillars of Islam, including having the children learn and write the Shahada, which is the Islamic conversion creed," she explained.

When she approached the Spring Hill Middle School teacher and principal and asked if there would be similar lessons on Christianity and Judaism, she discovered that the upcoming lessons are only on Hinduism and Buddhism. The only difference in the future lessons is that the students will not be memorising a creed dealing with those religions.

However, Maury County school officials insist that the public schools have committed no constitutional violations, stating that they merely "covered some sensitive topics" that "caused some confusion."

The ACLJ could not disagree more. "That's outrageous. The indoctrination of students with the precepts of converting to Islam and forcing them to recite 'Allah is the only God' aren't 'sensitive topics;' it's unconstitutional," it said.

School officials added that Christianity will be taught once students reach the "Age of Exploration" in the eighth grade. By then, students will learn about Christians persecuting other Christians in different countries in Western Europe, they added, in a transparent display of their bias against Christianity.

But that's not even the worse of it. One parent from Williamson County, also in Tennessee, said his son was forced to recite things in Arabic without even being told what they meant.

Meanwhile, students in Madison, Wisconsin, were given an assignment to "pretend you are Muslim."

In Florida, students were tasked to recite the Five Pillars of Islam as a prayer and perform Muslim rituals.

"Suspiciously, the textbook discussing Islam had chapters missing. Which chapters? Those on Christianity and Judaism," the ACLJ noted.

"To put this in perspective, imagine the outcry from the ACLU, Freedom From Religion Foundation (FFRF), and other leftist and angry atheist organisations if a study guide stated, 'Jesus is the Son of God,' and forced children to recite the Lord's Prayer. These organisations would be beside themselves claiming indoctrination of our public school students," the ACLJ said.

The conservative, Christian-based organisation is calling for the protection of religious liberty and a stop to Islamic indoctrination. The ACLJ said it is now taking action against schools that censor Christianity and promote Islam.