Polish and Russian football fans clashed in Warsaw ahead of their Euro 2012 group match on Tuesday.
Fighting broke out between the two sets of supporters as they walked towards the stadium.
The Russian fans had been celebrating their country’s national day and there were an estimated 20,000 in the Polish capital for the hotly-anticipated game.
Some 6,000 police officers roamed the streets in an attempt to keep the peace.
They tried to break up the scuffles but fans threw missiles, including rocks, flares and bottles.
Warsaw police did not comment on how many people were injured in the fighting.
Tensions run high when both countries meet at sporting events, given the intense rivalry between the two nations that stretches back centuries.
Russia occupied Poland for more than 130 years.