(JTA) — The Simon Wiesenthal Center issued a scathing denunciation of Croatia’s national soccer team on Wednesday, slamming the participation of a “fascist” singer in celebrations organized to mark the team’s return home from the World Cup earlier this week.

Members of the second place Croatian team invited singer Marko Perkovic, also known as Thompson, to ride with them as they made their way from the airport to the capital Zagreb on Monday, Balkan Insights reported.

The Simon Wiesenthal Center’s Dr. Efraim Zuroff described Thompson as an Ustasha sympathizer, referring to a Croatian nationalist movement which collaborated with the Nazis and participated in the Holocaust. Thompson is known for his songs about concentration camps and the murder of Serbs.

“Marko Perkovic has never missed an opportunity to transmit his hateful messages. It is no accident that numerous people show up at his concerts wearing Ustasha uniforms and/or symbols and give Ustasha salutes,” Zuroff said. “He should not be an honored guest anywhere, let alone at one of the biggest gatherings in democratic Croatian history to celebrate a magnificent sporting achievement. Luka Modric might indeed have deserved to be World Cup Most Valuable Player, but for inviting Thompson to sing he deserves a red card.”

FIFA, the world governing body of professional football, fined Croatian assistant coach Ognjen Vukojevic 15,000 Swiss Franks last week for using the Ukrainian phrase “Slava Ukrainy” (Glory to Ukraine), which is associated with the Organization of Ukrainian Nationalists, a far-right group which collaborated with the Nazis and killed thousands of Jews and Poles.