Police have made over 140 arrests in connection with clashes between Poland and Russia fans in Warsaw and expect to add to that number as investigations continue.
Euro 2012 co-hosts Poland drew 1-1 with Group A rivals Russia at the National Stadium on Tuesday night, but the game was surrounded by violent incidents in the city.
Prior to kick-off, thousands of Russian fans marched on Poniatowski Bridge to mark Russia Day - considered a provocative gesture by some Poles, whose nation was subjected to decades of rule by Moscow.
Flashpoints occurred there and at the designated Fanzone in Plac Defilad Square. Police are understood to have deployed water cannon and rubber bullets in response.
Officers from the Anti-Riot Unit and the Criminal Department are involved in the ongoing operation, and the police said they expected the number of arrests to grow.
A statement from the Polish police, released via www.policja.pl, said: "There are more than 140 hooligans caught by the police because of disorder in Warsaw - firstly during the march to National Stadium, and secondly in the Fanzone in Plac Defilad Square.
"Among the kept persons, there are fans of both teams - Russian and Polish. All the incidents took place before the match. There are 10 persons,who are injured: seven Polish, two Russians and 1one German - their lives are not in danger.
"The police operation is still ongoing. The police officers are checking the surveillance system, police cameras and [plan to] identify the hooligans who took part in the disorder. Further arrests are planned.''
It has since been revealed that there were lesser incidents of violence while the match was being played and that the injury toll had risen to 15.
Trouble flared despite a huge security operation in the Polish capital, where authorities had been extensively trained in anti-riot operations prior to the tournament.