The mayor of Bonn has banned over-exuberant Japanese fans from jumping into the river Rhine during the World Cup. Thousands of ecstatic fans celebrated the progress of co-hosts Japan into the last 16 four years ago by leaping into a river in downtown Osaka. Several injuries were reported. Bonn city officials are anxious to avoid a repeat should Japan advance from World Cup Group F and have warned visitors of the Rhine's strong current. "The quality of water is fine but the current is very strong so it is extremely dangerous," Bonn Mayor Baerbel Dieckmann told reporters. "We will ban supporters from swimming in the river."