German football federation (DFB) president Theo Zwanziger and league supremo Reinhard Rauball have called for tough action against troublemakers after a latest round of fan violence at midweek cup matches.Dynamo Dresden fans misbehaved around their team\'s cup match at Bundesliga champions Borussia Dortmund on Tuesday, with the game interrupted three times, 17 people injured and 15 arrested.On Wednesday, Kaiserslautern fans caused trouble in Frankfurt which left at least eight police officers injured and eight fans arrested. One fan was taken to hospital with severe injuries after being pushed onto the track ahead of an approaching train at Frankfurt station.\"The development is frightening,\" Zwanziger told Thursday\'s edition of the Bild daily.The DFB has launched investigations against the Dresden fans and is expected to probe the incidents in Frankfurt as well.Zwanziger said that the police alone cannot deal with the issue. He suggested that the DFB will look into whether standing areas in stadiums, which are still allowed at German matches, may be abolished.Rauball said that \"we will not let our game of football be destroyed\" and warned that the violent fan scene was bigger than originally believed.\"We pull wool over our eyes if we only speak of \'a few idiots,\'\" said Rauball.