At least 10 football fans have been injured and more than 140 arrested after violent clashes at the Euro 2012 match between Russia and Poland in Warsaw.
TV footage showed fans running away from exploding fireworks and flares on the Polish city's streets.
Several people were seen lying injured and bleeding on the ground, with one appearing to be seriously hurt.
Police said the injured included seven Poles, two Russians and one German.
Violence also broke out beside the stadium with Poland and Russia fans fighting and hurling stones at each other.
Russian fans also clashed with police on a bridge near the national stadium and officers were later seen making arrests.
Police said they were also studying CCTV footage to try to identify others involved.
Heavily-armed riot police who had been present in large numbers during the afternoon used a water cannon, rubber bullets and tear gas to try to disperse the troublemakers before the 7.45pm kick-off.
The two countries share a difficult history, including decades of Moscow's rule over Poland during the Cold War.
Many Poles had asked their leaders not to allow the Russians to march as a group in Warsaw, seeing it as an act of provocation.
The march, which involved 5,000 Russian fans, was considered a huge security challenge.
In addition the game was held on Russia's independence day and just before kick-off, a huge flag was unfurled with the highly inflammatory slogan "This Is Russia".
The fan violence was the worst of the European championship so far.
On Sunday, Russian football fans attacked four stewards following the team's opening tournament match in against the Czech Republic.