The mayor of Moscow has said that the real number of coronavirus cases in the Russian capital was actually around 300,000, a figure more than three times higher than the official total, the TASS news agency reported.
Authorities have reported 92,676 cases of the coronavirus in Moscow.
The number on confirmed cases of Covid-19 in Russia surged to 177,160 after a record daily rise in infections, meaning it now has the fifth highest number of registered cases in the world and more cases than in Germany or France.
A total of 11,231 new cases were diagnosed in the last 24 hours.
Russia's official death toll, which remains far lower than in many countries, rose to 1,625 after 88 people died overnight, authorities said.
Officials credit mass testing for identifying large numbers of people with only mild symptoms, but some say the discrepancy is due to how the death count is calculated.
"If someone dies of a heart attack but has been diagnosed with Covid-19, the official cause of death will be heart attack," said Sergei Timonin from Moscow's Higher School of Economics.
"It will only be at the end of May when the April statistics come out that we'll see the true death count from Covid-19 in Russia," he said.
As of yesterday, Russia ranked sixth in the world for virus cases but its death rate of 0.9% is far lower than in the other top 10 countries.
By comparison, Germany, often lauded for its health service's response to the virus, has declared a death rate of 4.2%.
Russians have widely disputed the figures, prompting the health ministry and the public health watchdog Rospotrebnadzor this week to insist the numbers reflect the country's rapid response to the pandemic.
Sergei Sobyanin, Moscow's mayor, said that confirmed cases were rising in the capital because authorities had sharply increased testing and that the situation had actually somewhat stabilised.
Russia says it has carried out more than 4.8 million coronavirus tests.
President Vladimir Putin has backed a plan put forward by Mr Sobyanin to gradually begin lifting some lockdown restrictions next Tuesday, allowing for instance certain industrial facilities to begin working.
Moscow and other Russian regions are in their sixth week of a lockdown.
The capital's residents have been told to stay at home except in certain circumstances such as going out to buy food and medicine. They must obtain a digital permit to travel anywhere by public or private transport.
Russia's relatively low death rate has prompted some Kremlin critics to suggest the authorities may be covering up the real toll of the outbreak by failing to correctly identify Covid-19 deaths as such.
The authorities deny those allegations, pointing out that Russia's coronavirus outbreak began later than in many other countries, allowing it to better prepare for the pandemic.
Russia now has the fifth largest number of cases in the world, according to a tally kept by the John Hopkins University in the United States.
