Fans of top Bulgarian club Levski Sofia hurled stones and bottles in their league match at Pirin Blagoevgrad on Sunday night, injuring eight police officers, the interior ministry said on Monday.
Nine people were detained after the incidents at the Hristo Botev Stadium in the southwestern town of Blagoevgrad where Levski, second placed in the league, secured a laboured 1-0 over relegation-threatened Pirin.
Two of the injured policemen were kept in hospital, suffering concussion, the ministry said. TV footage showed several policemen running away as they came under attack from Levski fans.
Levski have a long history of crowd violence and racism.
A 30-year-old man was killed by a bomb after Levski's clash with bitter city rivals CSKA Sofia in 2000 and hooliganism and arrests have been rife since then.
In 2014, Levski was fined by the Bulgarian Football Union after fans openly mocked a UEFA anti-racism campaigns, holding up a banner stating "Say 'Yes' to racism" and doctoring the UEFA logo during a league game.
The club was also fined after fans displayed a banner showing a swastika and another marking what would have been Adolf Hitler's birthday during a domestic game in 2013 and for racist behaviour by fans during a Europa League match against Bosnia and Herzegovina's Sarajevo in 2012.Published 17 May 2016, 00:24 IST