A club security guard was attacked at a hotel in Munich....
Cadena Ser reports that around 20 followers of the extreme left-wing group were involved in the incident, which resulted in the guard suffering head injuries.
It is thought that the radicals are in Munich with the intention of going to the match, even though the club has told UEFA, Bayern Munich and the German police to identify them and to not let them into the stadium.
The incident is believed to have begun when the group descended upon the hotel on the outskirts of Munich, where the players and team are staying.
They then approached the security guards, recognisable by their orange jackets, and asked if they were at the hotel to protect Joan Laporta.
Straight afterwards, they attacked one of the guards and struck him the face, resulting in him suffering injuries.
A Barcelona spokesman is reported to have said that the ultras "have been able to obtain tickets to the game not through the club".
There will now be an attempt to hunt down the group and to ensure that they do not get into the stadium for the game later this evening.
James Walker-Roberts, Goal.com