Uefa President Michel Platini has issued a plea to fans travelling to Saturday’s deciding Euro 2012 fixtures in Group A, asking them to "behave themselves".
There were clashes between Poland and Russia fans ahead of their 1-1 draw on Tuesday night in Warsaw, when thousands of Russians marched through the Polish capital during a celebration for Russia's national day.
Poland face Czech Republic and Russia play Greece in Saturday night's fixtures, and Platini has urged supporters not to replicate Tuesday’s scenes.
"I appeal to all fans that are going to Warsaw or Wroclaw tonight as we prepare for the deciding matches in Group A to conduct themselves with dignity and respect, and to behave themselves this evening at the stadiums and in the cities," Platini said in a statement.
"Uefa Euro 2012 is a celebration of football and I invite the fans, the vast majority of whom have conducted themselves in an exemplary manner so far, to continue to do so for the remainder of the tournament.
"Of course, there is rivalry and passion, and all teams want to win – but we must remember that the results on the pitch are what really matter."