Moscow's authorities have more than doubled the official death toll from Covid-19 in the Russian capital for the month of April.
The city's health department now says 1,561 people died from the disease - not 639 as initially announced.
The department stressed that the new tally included even the most "controversial, debatable" cases.
Moscow-based reporters had said the official numbers were too low, but were accused of fake news and distortion.
Confirmation that the numbers had been under-reported emerged before Russia announced 232 new deaths, its biggest daily death toll during the pandemic so far.
With 8,572 new recorded infections, Russia has the third highest number in the world of 387,623 cases. The official number of deaths stands at 4,374.
The government says the country's mass testing programme is responsible for that low mortality rate - but many believe the numbers are in fact far higher.
Although the number of new daily infections is down from a peak of over 11,000 earlier this month, health officials in Russia's second biggest city, St Petersburg, say hospitals there are running at peak capacity.
Moscow's health department said the death toll was revised following post-mortem examinations.
They had confirmed coronavirus as the cause of death in 169 cases where tests had initially been negative.
In addition, 756 people who died of other causes in April had tested positive for coronavirus. The officials said in many cases here the virus was a significant factor, playing the role of a "catalyst".
This new methodology is likely to mean the death toll will increase across the country, although Moscow was the epicentre of the epidemic for many weeks, the BBC's Sarah Rainsford reports.
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Muscovites will be allowed to go for regular walks from Monday as the city slowly lifts its lockdown
The Moscow health department stressed that even the new count put the Covid-19 mortality rate for the city at under 3% - suggesting that was well below comparable cities, our correspondent says.
But the authorities also conceded that the figures for May would be higher.
In a separate development on Thursday, a group of well-known Russian journalists were arrested in Moscow as they took part in single-person protests over a 15-day jail term handed down to a colleague.
The journalists accused police of using the Covid-19 outbreak to crack down on activists. Most have since been released, but charged with various offences.