The Liverpool managing director Ian Ayre has admitted that Zenit St Petersburg's recent racism problems are a "major concern" for the club ahead of Thursday's Europa League tie in Russia.

A Zenit fans group, Landskrona, published a manifesto in December calling on the club not to sign black, South American or gay players, complaining that "black players are now being imposed on Zenit practically by force". It said the lack of black players at Zenit was important to the club's identity, and added that fans were also "against representatives of sexual minorities playing for Zenit".

It prompted Liverpool to approach the game's authorities ahead of their visit to St Petersburg for a last-32 tie this week. "It's been a major concern for us," Ayre told Liverpool's official website, "so I wrote to Uefa very recently expressing our concerns to them – and also to Zenit themselves. We await some responses in that regard.

"The most we can do is make our feelings clear ahead of the game, and hope that we get an adequate response and adequate support on the night."

Ayre said travelling Liverpool fans would be issued with guidance on what to expect and how to behave, while the players would be briefed on how to react in the event of any racism or trouble.

"We do plan to speak to the players about it," Ayre said. "As with everything, the players have a lot to take on board around such a big game – so we're going to do that just ahead of the game. The most important thing for our players is that they remain professional throughout this. We certainly won't tolerate that type of attitude or any of those types of incidents from our team.

"So the important thing is that we let them know how we expect them to act if there is an incident. I'd much rather we take the incident off the pitch and we deal with it. Obviously the referee has a role to play within that. But we'll be briefing our players of what's acceptable and what's not.

Ayre added that his stadium manager, Ged Poynton, and club secretary, Zoe Ward, had travelled to St Petersburg to look at the facilities and meet Zenit and Uefa officials, and said they were aware of Liverpool's concerns.

The unveiling of the Zenit fans' manifesto added to concerns about racism at the 2018 World Cup, which will be staged in Russia, and followed other incidents involving the club's followers. Zenit were fined by the Russian Football Union after one of their fans offered a banana to the Anzhi Makhachkala left-back Roberto Carlos before a match between the two sides in March 2011.

Zenit were the only top-flight Russian team without a black player until the summer signings of the Brazilian forward Hulk and the Belgian midfielder Axel Witsel.