Detectives investigating disorder following a demonstration in Rotherham last month have issued CCTV images of men they want to trace.
Violence broke out in Wellgate in Rotherham town centre during a Britain First demonstration in September.
Missiles including bottles and bricks were hurled during the incident, injuring a number of people.
Police have so far charged 19 men - 15 from Rotherham and five from West Yorkshire - with violent disorder.
Call South Yorkshire Police on 101.