Legia Warsaw ultras are causing fear ahead of the Real Madrid - Legia Champions League match at the Bernabéu on Tuesday evening.
The Teddy Boy 95 ultras, amongst others, are considered to be some of the most violent in Europe and around 300 are thought to have managed to secure a ticket for the match.
Spanish government to put out 2,000 security personnel
Faced with the possibility of disturbances, vandalism and possible violence, the Spanish government has confirmed in a statement that it has approved special security measures for the game, both before, during and after, in and around the Santiago Bernabéu stadium.
Around 2,000 police and security personnel will be charged with ensuring the game takes place with no incidents; an extremely large police presence when compared with other events. For example for the Atlético-Bayern Champions League game there were only 500 personnel deployed, and for the recent Día de la Hispanidad parade, with the Spanish King and most major politicians present, just 1,500.
In addition to the standard police personnel, there will also be special units deployed, given the fears over the violent nature of the visiting ultra groups.
Legia Warsaw - Real Madrid to be played behind closed doors
The return leg in Poland, on 2 November, will take place behind closed doors after incidents at the Legia - Dortmund match.