UEFA’s top referee has vowed to crack down on players arguing with referees and “mobbing” them on the field at the upcoming European Championship in Germany.

Roberto Rosetti, UEFA managing director of refereeing, addressed a gathering of coaches from the 24 competing teams on Monday in Germany and called on them to ensure their players show respect for game officials.

“Unacceptable players’ behaviour is a problem for officials. The players are following you and, if you are calm, your players are more calm,” he told the coaches, according to a UEFA statement on Tuesday.

“We want to avoid unnecessary cards and protect the image of the game, so we will be strong with mobbing and clear dissent. This is about protecting the image of the game and a positive legacy for future generations. We have to do something and we need you because you are super important for us.”

Rosetti is an experienced Italian referee who oversaw the European Championship final in 2008, when Spain beat Germany 1-0.

UEFA also said it will make a decision soon on whether to allow teams to pick 26 players instead of the usual 23 for the tournament.

The expanded squads were used as a temporary measure at the last European Championship in 2021 to allow players to be replaced quickly if they tested positive for COVID-19 while in camp.

Netherlands coach Ronald Koeman argued last month for a return to 26-player squads because “you have to deal with more injuries these days,” but Germany coach Julian Nagelsmann disagreed in comments Monday.

Nagelsmann said he favoured sticking with 23 because he was concerned about the atmosphere in a larger squad suffering if too many players aren’t getting game time.

UEFA said there was no consensus among the coaches at Monday’s meeting.