Liverpool and Manchester United fans have been told there will be a “visible police presence” in Moscow next week.
The Premier League clubs both have Champions League group matches in the Russian capital.
A combined total of 2,000 fans will make the 3,200-mile round trip from the north-west with Liverpool playing Spartak Moscow on Tuesday and United taking on CSKA Moscow a day later.
United have told fans “not to wear club colours” or “walk around Moscow alone”.
Liverpool say the Russian authorities are aware the two clubs are in Moscow at the same time so a visible police presence can be expected “wherever groups of Liverpool and Manchester United fans congregate, including at your accommodation”.
Liverpool opened their campaign with a draw against Sevilla at Anfield on 13 September, whilst United defeated FC Basel at Old Trafford.
Russian hooligans attacked England fans in Marseille at the 2016 European Championship.