PAOK and AEK hooligans clashed at the Panthessaliko Stadium ahead of their sides’ Greek Cup final on Saturday.
About two hours before kick-off, PAOK and AEK hools entered an unguarded footbridge located over the stands and attacked each other.
The fight lasted for about 30 minutes before riot police intervened with stun grenades and tear gas.
At least 11 people were taken to hospital with injuries, two of them in serious condition. Another 40 or so wounded people were treated on site.
The start of the game was delayed about half an hour.