Berlin police have taken 71 fans into custody since Wednesday night around the European Conference League match between Union Berlin and Dutch side Feyenoord. Police said that more than 1,000 Dutch fans had arrived on the eve of Thursday’s game and that it was able to prevent fights between both camps, detaining supporters from each club. It was not clear yet whether these fans would remain detained until after the game. Some 30,000 fans are permitted to attend the game in the Olympic Stadium, 5,000 of them from Rotterdam. A major security operation is in place after several incidents around t…