Russia reported 852 deaths from COVID-19 in past 24 hours on Tuesday, above the previous all-time high reported last week amid a spike in new cases.
The authorities reported 21,559 new coronavirus cases in past 24 hours, slightly down from 22,236 cases on Monday.
The new figure brings the country's total deaths from COVID-19 to 205,531 -- the highest toll in Europe.
Authorities have been accused of downplaying the severity of the outbreak.
Under a broader definition for deaths linked to the coronavirus, statistics agency Rosstat reported in late August that Russia had seen more than 350,000 fatalities.
Russia, the world's fifth worst-hit country with more than seven million infections, has seen cases climb since last month as vaccinations stall.
Moscow, the epicentre of Russia's outbreak, has experienced a spike over the past week, with authorities warning of rising hospital admissions.
Deputy mayor Anastasia Rakova has said that the highly contagious Delta variant now accounts for all of the cases in the Russian capital.
Authorities face a vaccine-sceptic population, with polls showing that a majority of Russians do not plan to get jabbed.
The Kremlin initially set a goal of fully inoculating 60 percent of Russia's population by September, but later dropped that target even though free jabs have been available since early December.
As of Tuesday, only 28 percent of the population had been fully vaccinated, according to the Gogov website, which tallies Covid data from the regions.
