Fans of Morocco's Wydad Casablanca clashed with police inside the Mohammed V stadium after their match against arch-rivals Raja on Saturday.
Vardar fans clashed with police in the first half of the match.
Partizan hooligans pinched some flags belonging to Augsburg fans during Thursday's Europa League match in Belgrade.
Irate Levski fans clashed with riot police after a defeat of their team.
Santiago Wanderers and Colo-Colo fans clashed at the Elias Figueroa Brander stadium before their Primera Division match on Sunday.
Trouble flared at the end of Sunday's game between Lugano and Grasshoppers when supporters came on to the pitch.