A year in which racism and xenophobia have marred European soccer has brought another brazen act of intolerance. The largest fan club of Zenit St. Petersburg, the two-time defending Russian champion, has demanded that the team include no black or gay players.

The prominent group of Zenit supporters, known as Landscrona, posted a letter on its Web site on Monday, saying it wanted to preserve the traditional identity of the team by signing only homegrown players or those from Slavic nations like Ukraine and Belarus, from the Baltic nations or from Scandinavia. The club did not have a black player until late summer and has a history of prejudiced behavior by some of its fans.

“Dark-skinned players are all but forced down Zenit’s throat now, which only brings out a negative reaction,” the fan group said, adding that gay players were “unworthy of our great city.”

Antiracism officials said the episode was another embarrassment for Russia as it prepares to host the 2018 World Cup and for Gazprom, the government-controlled natural gas company that owns Zenit St. Petersburg and is a sponsor of the Champions League, Europe’s most important club tournament.