Manchester United have advised their fans heading to Rostov not to wear the club's colours while in the Russian city.
United face FC Rostov on Thursday night in the first leg of their Europa League last-16 tie.
There are concerns over the safety of supporters going over for the game, with English and Russian fans having clashed in violent scenes during the Euro 2016 finals in France last summer.
And, according to the Telegraph, United's head of ticketing and membership Sam Kelleher has sent a letter to fans travelling to Rostov which says: "For your safety and security you are advised not to wear Manchester United colours when in Rostov, or attract attention to you presence in the city.
"It is also advised you stay in groups where possible, and do not walk around the city alone.
"It is not just opposition football fans who may potentially pose a risk to your safety, and incidents of serious disorder during the European Championships in France last summer, involving violent individuals and groups emanating from Eastern Europe, should be remembered when considering your movements and actions, and any potential risk."