Russian President Vladimir Putin has said a locally developed vaccine for Covid-19 has been given regulatory approval after less than two months of testing on humans.
Mr Putin said the vaccine had passed all the required checks, adding that his daughter had already been given it.
Officials have said they plan to start mass vaccination in October.
Experts have raised concerns about the speed of Russia’s work, suggesting that researchers might be cutting corners.
Amid fears that safety could have been compromised, the World Health Organization (WHO) urged Russia last week to follow international guidelines for producing a vaccine against Covid-19.
On Tuesday, the WHO said it had been in talks with Russian authorities about undertaking a review of the vaccine, which has been named Sputnik-V.
Currently, the Russian vaccine is not among the WHO’s list of six vaccines that have reached phase three clinical trials, which involve more widespread testing in humans.
More than 100 vaccines around the world are in early development, with some of those being tested on people in clinical trials.
Despite rapid progress, most experts think any vaccine would not become widely available until mid-2021.
Calling it a world first, President Putin said the vaccine, developed by Moscow’s Gamaleya Institute, offered “sustainable immunity” against the coronavirus.
He said he knew the vaccine was “quite effective”, without giving further details, and stressed that it had passed “all needed checks”.
Putin also said the vaccine had been given to one of his daughters, who was feeling fine despite a brief temperature increase.
“I think in this sense she took part in the experiment,” Mr Putin said, without specifying which of his two daughters had received the vaccine.
“After the first injection her temperature was 38 degrees, the next day 37.5, and that was it. After the second injection her temperature went up slightly, then back to normal.”
It is rare for President Putin to talk publicly about his daughters – named Maria Vorontsova and Katerina Tikhonova in media reports – and their lives have been shrouded in secrecy.