Tests used throughout Russia to determine if someone has the novel coronavirus or not often give the wrong result, Moscow officials said on Thursday, in a statement further calling into question the veracity of official statistics, Reuters reports.

The blunt admission by Moscow's department of health came on the same day as the Russian capital's mayor, Sergei Sobyanin, said the real number of coronavirus infections was more than triple the official figure.

The disclosure that test kits often wrongly say that people with late stage Covid-19 are free of the disease means the real number of infections in Russia — at 177,160 already the fifth highest in the world — is likely to be even higher.

It also means that people with the virus have been given the all-clear by doctors and allowed in some cases to go home where they could infect other people. Reuters has verified at least one case where that happened and the individual infected someone else in their household who later died.