Students at a Mississippi high school say they won’t be returning to class while they protest the removal of their prayer group from school hours to after school.

News outlets report students at Tylertown High School in Southern Mississippi walked out of class Wednesday and won’t return until their faith-based program First Priority is reinstated to its normal time, during school hours.

Student Tyasia Shackleford says First Priority has existed for 15 years and meets once a month to praise God. Student Kaitlynn Brown says students “want to celebrate God” and the school took that away.

It’s unclear why the program was removed from school hours.

Walthall County School superintendent Wade Carney says all student-led organizations cannot meet during instruction time. He says they can meet before or after school.