Mayor Sergei Sobyanin said data suggests between 2 and 2.5 per cent of people living in the Russian capital have been infected, meaning 300,000 cases.
That figure is more than three times Moscow’s official tally of 92,676 cases and is slightly less than double the total for the whole of Russia, which stands at 177,160.
If those cases were added to the country’s official tally, it would make it the second-most infected nation in the world – second only to the US.
But his revelation comes against the backdrop of medics mysteriously falling from windows after they challenged the official government line on coronavirus.
Two senior women doctors in Russia have died recently after falling from hospital windows amid reports they had challenged their superiors over a lack of PPE for coronavirus patients.
Meanwhile paramedic Alexander Shulepov, 37, sustained serious skull fractures falling from another window after also complaining about a lack of PPE.
Russia officially confirmed another 11,231 cases of coronavirus on Thursday, bringing the total number of infections from 165,929 to 177,160.
The total marks Russia’s single-largest daily rise in infections since the start of the outbreak, and comes after four consecutive days where the total was over 10,000.
The figures mean Russia officially has the sixth most coronavirus cases in the world, but has a mortality rate of just 0.9 per cent.