"At the moment, 81 samples of the British strain and six South African ones have been isolated in Russia. This suggests that we are still in contact with other countries of the world, all of these cases are imported. Today, the prevalence of these strains is high in Europe, Asia, the South American and, of course, the African continent," Popova told the Russian Izvestia newspaper.

She warned that a growing number of coronavirus cases of the British and South African variants are being registered across the world and urged Russians not to travel abroad.

"While in a number of European countries 60-70% of all finds are precisely the British strain, in our country, it is still not widespread. Thanks to our restrictive measures inside the country and on the borders. Therefore, today it is better not to travel outside the country if there is no special need," Popova said.

According to the Rospotrebnadzor head, a total of over 20 coronavirus strains have been isolated in Russia; these strains, in turn, have various mutations that are now being studied.

On Monday, Russia reported 8,646 new COVID-19 cases, down from 8,817 the day before, taking the overall tally to 4,589,540, according to the country's coronavirus response center.