In a short statement posted on Facebook on Sunday, Cracovia hooligans wrote that they had broken off their relations with Ajax hooligans.
Clashes broke out inside the Athens Olympic Stadium ahead of AEK's Champions League match against Ajax on Tuesday.
River Plate fans attacked the Boca Juniors team bus before the second leg of the Copa Libertadores final on Saturday, leaving several players injured.
Valenciennes and Lens fans clashed on the street ahead of their Ligue 2 match on Saturday afternoon.
Ajax fans were attacked by a mob of Benfica hooligans in the Portuguese capital after their Champion League match on Wednesday night.
Egaleo hooligans clashed with riot cops before the side’s third division match against Chalkida on Sunday.
Flamengo fans fought among themselves in the stands at the Morumbi Stadium during half-time of their match against Sao Paulo on Sunday.
Brøndby hooligans clashed with riot police after the side's 1-0 defeat to bitter rivals FC Copenhagen on Sunday.
Members of Rayo's Bukaneros and Barcelona's Boixos Nois clashed before Saturday's La Liga match.
Angry Zeljeznicar fans stormed the pitch following a 1-0 home defeat to Zvijezda 09 on Sunday.
Hertha Berlin ultras clashed with riot police at the Westfalenstadion during Saturday's Bundesliga match with Borussia Dortmund.
Slavia Prague fans clashed with stewards inside the Parken Stadium after the side's Europa League match against FC Copenhagen on Thursday night.