Police made 11 arrests following trouble at Leeds United's game with Birmingham City.
There was disorder both inside and outside United's Elland Road stadium on Saturday, West Yorkshire Police said.
Birmingham fans clashed with police and stewards at the final whistle and then there was a "public order incident" in the coach park, the force said.
The arrests were mainly for public order offences. Minor injuries to several match stewards were reported.
BBC Leeds sports editor Jonathan Buchan described on Twitter "terrible" scenes inside the stadium from Birmingham City fans, with "a few stewards receiving punches and kicks as they tried to apprehend a Birmingham fan who ran onto the pitch".
Police said officers were deployed between supporters outside the ground for about 45 minutes before fans dispersed.
Match commander Ch Insp Jon Arrowsuch said the 11 arrests were made both inside and outside the stadium.
"Clearly these were scenes no-one would wish to see and we will be examining CCTV footage and working with both clubs as we investigate what took place," he said.