Holland: Police and Feyenoord fans clashed.
Saturday morning a large group of Feyenoord fans wanted to attend the last training before the derby with Ajax. It's a popular tradition to attend the last training before this important match.
This time the mayor of Rotterdam decided to prevent any fans to gather at the training due to the COVID-19 restrictions. When supporters arrived police had already lined up to stop them from going any further. Tension raised and finally ended with riots.