UEFA has received a stern warning that any outcome arising from the Premier League's allegations against Manchester City could lead to "serious unrest" among its member clubs.
UEFA are set to investigate allegations of racial abuse directed towards Aberdeen striker Pape Habib Gueye.
Professional Footballers' Association chief executive Maheta Molango has warned that players will be angry with UEFA president Aleksander Ceferin's salary cap push.
UEFA will investigate allegations that Barcelona made payments to referees' committee member Jose Maria Enriquez Negreira.
Real Madrid reject UEFA's compensation offer to fans following last year's Champions League final chaos.
UEFA have said they will reimburse all Liverpool supporters who attended last year's chaotic Champions League final between The Reds and Real Madrid at the Stade de France in Paris.