Manchester United have told supporters not to wear colours or 'attract attention' in Moscow as the Russian FA sent an extraordinary warning to those travelling.
Jose Mourinho's side face CSKA Moscow on Wednesday, with Russian police expected to be 'less than tolerant' during a week both United and Liverpool play in the city.
Around 2,000 fans are travelling from the North West and United are providing buses to and from the VEB Arena in a bid to combat potential conflict.
That comes as the head of the Russian Football Union's security committee, Vladimir Markin, claimed they will come down hard on troublemakers.