A Christian student group is filing a lawsuit against what its lawyers say was unconstitutional targeting of their free speech at North Carolina State University.

In a press release, Alliance Defending Freedom (ADF) claims that Grace Christian Life’s efforts to engage in religious discussion and invite students to participate in the group’s events were restricted by university officials — to the point where a permit was required to engage in discussions inside the student union building.

However, the lawsuit claims, this regulation was not applied to other student groups and at least one non-student group that engaged in similar action as Grace Christian.

The regulation states that “any distribution of leaflets, brochures, or other written material, or oral speech to a passersby” is required to “have the written permission of the Student Involvement [Office] in advance.”

“The courts have well established that a public university can’t require permits in this manner for this kind of speech — and certainly can’t enforce such rules selectively,” stated ADF Senior Counsel David Hacker in the press release. “Unconstitutional censorship is bad enough, but giving university officials complete discretion to decide when and where to engage in silencing students makes the violation even worse.”

The university told an ABC affiliate that they had not received the lawsuit, which was filed on Tuesday afternoon, and thus could not comment. In December, the university responded to an ADF letter and defended the constitutionality of its policies.