A video that showed a Minnesota high school student holding a pro-gun sign being escorted off campus during Wednesday’s national school walkout has gone viral.

A video posted by Facebook by user Kenny MacDonald showed a male student holding a sign that read, “Guns don’t kill people, people kill people” and being confronted by New Prague High School Principal Lonnie Seifert.

According to Mr. MacDonald, the student walked peacefully and quietly with his sign as fellow students participated in a nationwide walkout in honor of the 17 students and teachers who were killed in last month’s mass school shooting in Parkland, Florida. Other students, according to Mr. MacDonald, held signs that read, “Arm our teachers” but were not escorted off campus.

In the video, the school principal is seen leading the student away from the protest. According to Mr. MacDonald, the student was threatened to be put into a police car.

The video had been viewed more than 2.4 million times as of Thursday afternoon.

The New Prague Area school district issued a statement Thursday saying its policy regarding “distribution of non-school-sponsored material” requires students to obtain permission by the school administration at least 24 hours in advance.

“In compliance with the District’s policy ‘… to protect the exercise of students’ and employees’ free speech rights, [while] taking into consideration the educational objectives and responsibilities of the School District,’ the sign was moved to non-school grounds,” the statement said. “The District has an obligation to enforce this policy without regard to political viewpoint.”

The district said no one was disciplined and law enforcement was not involved with any of the students during the walkout.

“New Prague Area Schools fully respects and recognizes that students have free speech rights,” the district’s statement said. “Those rights, however, are to be balanced against the District’s responsibility to maintain a school environment focused on education. The District’s administration has an obligation to enforce the policy, which is known as a ‘time, place, and manner restriction.’”

Superintendent Tim Dittberner said the district is investigating the incident, the Jordan Independent newspaper reported.

A New Prague Police Department employee told the Jordan Independent that no report was made on the incident.