The fans of Anderlecht behaved in a bad way during their loss to West Ham.
Flares and seats were thrown by the Anderlecht supporters.
Two police officers were taken to the hospital, one for a broken wrist and the other for a head injury.
Two other officers were hit.
The spokesman for the Belgian club apologized for the behavior. We don't tolerate this kind of behavior. Uefa and our own fans will be involved.
The move was welcomed by the manager of the Hammers.
The police were called in to make sure the two sets of fans were kept apart.
"I thought I saw something moving," said the man. I didn't care about it. We want to draw more attention to it.
Crowd trouble takes focus away from everyone. Football clubs don't want to be attached to them. I don't work at Westham.