Over 180 people were detained  due to clashes that broke out between rival Russian and Polish football fans in Warsaw on June 12. Unrest started during the march organised to mark the Russian National Day, attended by thousands of visiting Russian fans ahead of the Poland-Russia Euro 2012 game at the National Stadium.
Concern about possible tensions had been expressed by several newspapers and public figures prior to the march, given the troubled history of the two countries. Hanna Gronkiewicz-Waltz , the Mayor of Warsaw, recognised the problem, but stated that “the Russian fans’ delegation promised that there wouldn't be any political exclamations on their part.”
Gronkiewicz-Waltz called the day of the march “the main challenge for the city during the Euro 2012 championship.”
The idea of holding the march had also caused quite some buzz among the Polish netizens. A few days before the march, Salon24 user szkielkooko wrote  [pl]:
Clashes during the Euro are inevitable. […] Polish hooligans will definitely oppose the march, and organise some spectacular fights to “repay the Russians” for the years of communism, partitions and the bloody supressions of the Polish uprisings in the 19th century. This kind of behaviour is almost openly encouraged by the right-wing journalists.
Salon24 user rybitzky also pointed out  [pl] the stance that the mainstream media took in this situation:
The mainstream media suddenly started to act as if they were completely crazy. Maybe the journalists got so sucked into the atmosphere of the Euro that they forgot their usual strategy of promoting the Polish-Russian reconciliation?
@polococto wrote  [pl]:
If the Mayor allowed a march of two rival Polish football teams through the city center, would anyone be surprised by the clashes?
@jakmarcin called for the reasonable evaluation of the unrest  [pl]:
The German media describe the clashes objectively, as a minor outburst of aggression on the both sides
Some people are interpreting the riots as part of the political game between the ruling party and the opposition.
@DziadekWaldemar wrote  [pl]:
There is only one political party in Poland that can gain from those clashes, and it's the right-wing [PIS ] and its supporters, they have links with the hooligans […]
Salon24 user mojsiewicz wrote  [pl]:
The ruling party is ready to burn down half of Warsaw only to stay in power. These clashes are the only thing that can draw attention of the public away from almost 3 million Poles living in poverty.
Some people point out that the hooligan clashes in Warsaw gained much more attention in the interational press than the “March of the Millions” – a massive protest rally organised on the same day in Moscow by the opposition.
@OlgaAlehno wrote :
WELL DONE PUTIN! A march of 200,000 opposing him, held in Moscow, was outdone by some minor clashes in Warsaw. […]