Russian President Vladimir Putin said Thursday that dozens of people in his entourage tested positive for the coronavirus before he went into self-isolation earlier this week.

The Russian leader, who announced in March he had been vaccinated, started self-isolating on Tuesday after being identified as a coronavirus contact.

"You know that unfortunately I had to cancel my visit to Dushanbe at the last moment," Putin said during remarks to a meeting of the Moscow-led Collective Security Treaty Organisation (CSTO), hosted in the capital of Tajikistan. "I am very sorry, but this is due to the fact that, as you know, cases of the coronavirus were detected in my inner circle," he said, speaking via video link.

"Not just one or two but several dozen people," he added. "And now I have to remain in self-isolation for a few days."

The 68-year-old Russian leader specified in late June that he had been vaccinated with Russia's homegrown Sputnik V after months of secrecy around the issue, but the Kremlin did not show images of the inoculation.

Putin in recent months has resumed his work trips and face-to-face meetings, but many of his contacts are still required to spend two weeks in quarantine.

Russia is among the countries hardest hit by the coronavirus pandemic – with the fifth-highest number of recorded cases according to Agence France-Presse (AFP) tally – and has struggled to rein in infections despite easy access to vaccines.

Authorities have struggled with a vaccine-skeptic population, with independent polls showing that a majority of Russians do not plan to be inoculated.