Russia registered more than 25,000 new coronavirus infections over the past 24 hours on Sunday, a number the country has not seen since January.
Particularly affected are the capital Moscow and the tourist metropolis St Petersburg, which on Friday hosted its seventh match during the ongoing European Football Championship.
Pictures from the fan zones showed many without the mandatory face masks.
Authorities on Sunday reported 663 new virus-related deaths.
Earlier in the week, Russia reported record numbers of coronavirus deaths for five days in a row.
Despite the the more contagious Delta variant fuelling the high numbers, no nationwide lockdown is planned, the Kremlin has announced.
However, there are increasing restrictions on public life in individual regions that are seeing a high number of infections, such as in Buryatia on Lake Baikal.
In Moscow, people are now only allowed into restaurants with a negative PCR test or with proof of vaccination. Employers in many sectors in the capital are obliged to enforce vaccinations of their employees.