The Russian giant is the only major side in the country to have never had a player of African descent, and this is something that 'Landscrona' are keen to see upheld.
"We're not racists, but we see the absence of black players at Zenit as an important tradition," the letter, which was also posted on the fan club's website, read.
"It would allow Zenit to maintain the national identity of the club, which is the symbol of St. Petersburg. We only want players from other brotherly Slav nations, such as Ukraine and Belarus as well as from the Baltic states and Scandinavia. We have the same mentality and historical and cultural background as these nations."
The letter also called for the club to reject "sexual minorities."
Ex-Zenit striker Alexander Panov has taken a dim view of the demands, and believes that fans should not have a say on transfers or club politics.
"If we don't have enough good players from St Petersburg, then what should the club do?" he asked. "All clubs around the world have black players. If they are absent from Zenit – it's Zenit's problem. I don't think fans should demand the club buy or don't buy certain players. The fans have the right to go to the stadium or stay home."
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