Students at an Arizona high school gathered Monday to stage a walkout protest after a student was forced to remove her Black Lives Matter T-shirt during school hours last week.

Mariah Harvard, 15, wore the shirt representing the social justice movement on picture day at Buckeye Union High School in Phoenix’s westernmost suburb on Aug. 23 and was ordered by administrators to take it off because it could “disrupt the education process,” Arizona's 12 News reported. School officials had received a complaint from another student.

Harvard complied and swapped her Black Lives Matter shirt for a plain, white shirt, but not before she posted a photo of herself in the controversial shirt on Facebook and wrote about the incident, which Harvard said all started because of an argument she had with another student who told her “black lives don’t matter” a few days prior. Harvard noted in the post that she had seen other classmates wearing political shirts that can been seen as offensive, like ones emblazoned with the Confederate flag that she claims have not resulted in any repercussions.

“While wearing the shirt I have been verbally attacked MANY times, I never meant to imply because black lives matter others don't!” she wrote. “On top of that while attending Buckeye I’ve seen a young lady who wore a Confederate flag shirt that clearly supports racism, the creator of the Confederate flag in his own words said, ‘As a people we are fighting to maintain the heaven-ordained supremacy of the white man over the inferior or colored race.’”

In response to the shirt ban, Harvard’s classmate, Genesis Santoyo, wore a Black Lives Matter shirt to school Wednesday and was also asked to change.

Harvard’s mother met Thursday with school administrators. One day later, Harvard’s clothing was questioned again when she was asked to remove her sweatshirt so school officials could see if she had worn the Black Lives Matter shirt underneath.

Buckeye administrators have since banned Confederate flag t-shirts along with clothing representing the Black Lives Matter movement. However, that didn’t stop Harvard, Santoyo and eight other students from holding a walkout Monday morning during class. They all wore Black Lives Matter shirts and held white signs with red lettering that said, “Vision For Black Lives.”

Students were joined by their parents and local politicians, civil rights groups and representatives from Black Lives Matter Phoenix, who all voiced their support of the students' right to self-expression in a nonviolent way. Arizona congressional candidate Isha Graves also offered her support for the students, telling the Arizona Republic that she was “proud they were standing up for what they believed in.”

School administration would not answer questions regarding the dress code policy during interviews with local media. A statement posted on the school’s website said the “district strives to remain politically neutral while allowing student expression” but could not allow said expressions to “interfere with the learning process and become a potential danger to students."