British World Cup fans have been warned that yelling pro-Brexit chants may bring sanctions by FIFA, soccer’s governing body.

FIFA warned fans of the “Three Lions” against “displaying insulting or political slogans in any form” and “uttering insulting words or sounds” during Thursday’s upcoming match in Kaliningrad, according to the UK Telegraph.

A FIFA spokesman added that “of course” fans could risk some sort of punishment for their team.

England’s game against Belgium comes as the UK enters into tough negotiations with Brussels to separate from the European Union after the 2016 referendum set the United Kingdom on the road to exit the multi-national organization.

Indeed, there have been warning signs that some may use the game as a Brexit platform as some have already taken to calling Thursday’s game the “Brexit derby.”

Pro-Brexit chants have already broken out at games in the past, including the 2016 European Championship where British fans yelled: “F**k Off Europe, we’re all voting out.”

British fans also raised eyebrows, recently, after being seen on video taunting Russian fans, giving Nazi salutes, and screaming anti-Semitic slogans. One UK fan was even banned for five years due to his behavior after an investigation by British police identified him.

British fans are far from the only fans to deliver ill-advised chants. Mexican fans have been under sanction by FIFA for years for yelling “Puto” at opposing teams, a term generally meant as a gay slur.

In 2016, the Mexican national team was even fined $20,000 by FIFA for its repeated use of the homophobic chant.

Follow Warner Todd Huston on Twitter @warnerthuston.