Swiss federal prosecutors say they are conducting an "ongoing operation" in an investigation of the 2006 World Cup organising committee as part of a wider probe of corruption linked to FIFA.
The office of Swiss attorney general Michael Lauber told The Associated Press that details of the operation should be confirmed later on Thursday.
German organisers of the 2006 World Cup, led by Franz Beckenbauer, have been under investigation by Swiss prosecutors and the FIFA ethics committee over alleged bribery and irregular payments of several million dollars linked to FIFA.
Beckenbauer headed his country's bid to win the hosting rights in 2000 in a tight vote ahead of a South Africa bid backed by Nelson Mandela.