Argentina's President Alberto Fernandez was injected Thursday with a dose of Russia's Sputnik V coronavirus vaccine, still undergoing Phase 3 trails.
"Today I received the Sputnik V vaccine," the president, 61, announced on his Twitter account, with a photo of him being jabbed by a nurse at Posadas hospital in Buenos Aires.
"Getting vaccinated means to be immune to the coronavirus. Let's do it," he added.
Russia in August registered Sputnik V -- named after the Soviet-era satellite -- months ahead of Western competitors but before the start of Phase 3 clinical trials, which left some experts wary.
Phase 3 is the final testing round before a drug is approved.
Its developers claim Sputnik V has been shown to be more than 90 percent effective in early trials, and Russia has already launched a vaccination campaign using the shot.
The Russian Direct Investment Fund, which helped develop the vaccine, says Sputnik has also been registered for use in Belarus, Venezuela, Bolivia, Algeria, Serbia, Paraguay, Turkmenistan and the Palestinian territories.
Argentina began administering second doses of Sputnik V to health personnel this week, having kicked off its own immunization campaign in late December.
Fernandez is one of the first world leaders to receive the Russian shot. In his tweet, he thanked Russia's Gamaleya laboratory for its work on the vaccine, and Argentina's health personnel for their "enormous commitment".
Argentina has also signed a deal to buy doses of the vaccine created by AstraZeneca and Oxford University. It is still negotiating for access to the Pfizer-BioNTech jab.
The country of 44 million people has registered 1.8 million infections and 46,000 deaths due to the Covid-19 pandemic.
Russia says the shot has been given to some 1.5 million people.