Fear of the turbulent relationship between Poland and Russia. © EuroFootball.com

In Poland, there is concern about a possible repetition of football hooligan riots.

There are rumors that about 2,500 Russians have arrived in Warsaw from Russia in recent days. Some of them, according to reports, seek revenge for the mass brawls a few days ago when Polish hooligans attacked Russians celebrating Russia's Independence Day and marching in the streets.

"At least two hundred serious individuals have arrived from Russia," sources say. It is speculated that the unrest may not be as widespread: the fights may take place in relatively small groups that agree in advance on the time and place.

For this reason, law enforcement forces have been strengthened on the city streets, and the Ministry of Internal Affairs of Poland is closely monitoring the events. This could become an incentive for unrest on the outskirts of the city.

This evening, Poland (2 points) will play against the Czech Republic (3 points) in Wroclaw, while Russia (4 points) will clash with Greece (1 point) in Warsaw. So far, neither team has lost hope of reaching the quarterfinals.