"Our main concern is the hools scene, the hools nearby, the Polish hools,? Nolle said. ?We know not much about the scene so we are worried because we don't know who they are, or how many coming."
Security concerns do not stop with hooliganism.
Senator Ehrhart Korting, Minister for Justice in Berlin, said, ?It's a question we have in the whole western world, Islamic terrorism.?
Korting said German authorities are only too aware of the threat, following the terrorist attacks in Madrid, London and elsewhere in Europe by al Qaeda sympathizers.
The German intelligence service B.K.A. has identified 21 of the 64 World Cup matches as posing high risks because of the participants. These mainly involve countries engaged in the Iraq war, particularly England and the United States.
Away from the tight security at the stadiums, there are fears that the many fan parties, expected to attract tens of thousands of people, could be considered soft targets for terrorists.
Authorities say they are as prepared as they can be.
"I think what we can do against it, we do,? Korting said. ?But we are a free country with free borders and you have a choice. Either you will have police state or have free countries."
On the streets of Berlin, residents appeared relaxed about security concerns.
Security preparations are likely to be tested in the coming weeks as German forces and their international counterparts work to ensure the safety of the millions of people heading to Berlin.