A school district in the U.S. state of Wyoming has lifted its ban on non-disruptive private prayer in its school cafeteria after a Christian group sent a letter threatening them with a lawsuit.

The Platte County School District #1 reversed the decision of the principal who told a student that students were not allowed to pray during lunch because they were pushing their religion on other students.

Last Oct. 15, students went to the back of the lunch room at Glendo High School and formed a small circle while one student prayed for their meal. The prayer did not create any disruptions or cause any problems in the noisy cafeteria, according to Alliance Defending Freedom, which sent the letter.

After lunch period, Principal Stanetta Twiford told one student about the purported rule. Twiford said if the students wanted to pray, they had to get permission and then go into the gym or hall away from other students.

The parent of three of the children discussed the situation with Twiford and District Superintendent Dennis Fischer, but the two stood by the ban, saying that the Constitution prohibited prayer because any other students observing it were a "captive audience," an information they claimed to read from the American Civil Liberties Union.

"No student should be prevented from engaging in private prayer alone or quietly with other students on campus," said ADF Legal Counsel Jonathan Scruggs, adding that the Supreme Court ruled that "the First Amendment protects the right to pray in a non-disruptive manner not just in private but in public, too."

In its letter dated Dec. 4, the ADF told the district that the "cafeteria prayer ban violates the First Amendment."

"The First Amendment requires schools to allow student speech so long as that speech is not materially and substantially disruptive," it read.

Superintendent Dennis Fischer sent a letter to ADF dated Dec. 17 to say that the district's attorney concurred that the students' prayer did not violate federal law and that he has advised Twiford "to let the students know that they can pray before meals in the manner they had in the incident in question."

After the incident, Fischer said "our staff and district have a better understanding of students' rights regarding prayer and how to handle future incidents."