Police and protesters clashed briefly in Ferguson just hours after the St. Louis suburb’s police chief issued an apology to the family of Michael Brown, a Black 18-year-old who was fatally shot by a White police officer last month.

Ferguson Police Chief Tom Jackson appeared outside the police department in civilian clothes late Thursday to assure protesters that there would be changes in the wake of Brown’s killing, The St. Louis Post-Dispatch reported. “All those things that are causing mistrust are being evaluated and we are going to be making changes,” Jackson said. The police chief started to march with protesters around 11 p.m.

Soon after, a scuffle broke out about 20 feet behind the chief and one protester was arrested. The Post-Dispatch said at least three other protesters were arrested after another confrontation.