Bayern Munich supporters were violently attacked by police at the Georgios Karaiskakis Stadium in Piraeus, Greece ahead of the club's Champions League match with Olympiacos. Many supporters have already left the stadium, and it is believed that most, if not all, will follow before the match finally kicks off.

Clubs running into trouble with police in southern Europe is a regular occurrence, but by all accounts from supporters and media inside the stadium, this attack by the police was wholly unprovoked.

UEFA has no issue punishing clubs for the behavior of their supporters but what about the police? Can you punish a club due to the actions of the police inside their stadium?

Hopefully, nobody is too seriously injured and can make a full recovery.

WARNING: The following videos show Bayern supporters being treated by medics in the stadium. There is a good amount of blood in the videos due to what appears to be many head injuries.

Es wird bereits erste Hilfe geleistet. Die #Polizei hat wohl den Fan attackiert! #OLYFCB https://t.co/jCjOrjTo7N — SPORT1 (@SPORT1) September 16, 2015