UEFA has charged AEK Athens and Ajax after clashes between fans marred their Champions League match on Tuesday.
There were ugly scenes before kick-off in Athens as home fans were pictured throwing flares and other missiles into the away section of the Olympic Stadium, with some images showing flames erupting on the terrace.
Riot police were also seen striking Ajax fans, some of whom were left with bloodied faces.
Police had also faced trouble from a number of supporters in central Athens earlier in the day and on Monday evening.
Petrol bombs were also used during those disturbances, with traffic blocked before order was eventually restored.