MOSCOW — The Russian capital on Monday has started offering a domestically developed coronavirus vaccine to children in the 12-17 age group amid the country’s biggest infection surge yet due to the spread of the highly contagious omicron variant.

Omicron is less likely to cause severe illness than the previous delta variant, according to studies. Omicron spreads even more easily than other coronavirus strains, and has already become dominant in many countries. It also more easily infects those who have been vaccinated or had previously been infected by prior versions of the virus.

Free shots of Sputnik M — a version of the Sputnik V vaccine that contains a smaller dose — became available last week to 12-17s in a number of Russian regions spanning from the region surrounding Moscow to the Urals to Siberia and the far east, with the capital being the latest addition to the list.

Moscow now has 13 clinics offering the vaccine to 12-17s, city authorities said.

Immunization of children in Russia comes as the country is facing a record-breaking surge of contagions, with health officials reporting six-figure tallies of new confirmed cases for three straight days. On Monday, the state coronavirus task force counted 124,070 new infections, another all-time high in the pandemic for Russia. The previous record, of 121,228, was reported the day before. Officials also reported 621 new deaths on Monday.

Despite the latest surge, the Russian authorities have resisted imposing any major restrictions. Kremlin spokesman Dmitry Peskov reiterated to reporters on Monday that there were no discussions of a nationwide lockdown.

Such a lockdown was imposed in Russia only once, in the spring of 2020, and lasted six weeks. In October 2021, many Russians were also ordered to stay off work for a week. But generally the government has steered clear of shutting down businesses.

Earlier this month, the country’s parliament indefinitely postponed introducing new restrictions for the unvaccinated, plans that proved unpopular among vaccine-hesitant Russians. Only about half of the country’s 146-million population is fully vaccinated, even though Russia was among the first nations in the world to approve and roll out a domestically developed shot.

Officials in Moscow and St. Petersburg sounded the alarm last week about coronavirus infections spiking among children and teenagers. Authorities in the Russian capital said Monday they were increasing the number of hospital beds for children with COVID-19.

The governor of St. Petersburg, Alexander Beglov, on Monday ordered school students from grades 7 to 11 to switch to remote learning starting from Wednesday and until Feb. 13. He also barred all minors from restaurants and cafes, shops selling nonessential goods, museums, theaters, cinemas, zoos, gyms, swimming pools and other recreational venues.

Russia’s state coronavirus task force reported a total of 11.8 million confirmed cases in the pandemic and 331,349 deaths — by far the highest death toll in Europe. However, reports by Russia’s state statistics service Rosstat, which uses wider criteria for counting virus-linked deaths, revealed much higher numbers.

Rosstat’s latest update, released on Friday, showed that some 681,100 people with COVID-19 died between April 2020 and December 2021. The number of COVID-related deaths in 2021 — 517,800 — was more than three times higher than in 2020 — 163,300. The tally includes deaths in which COVID-19 wasn’t considered the main cause.

Peskov on Monday called the numbers reported by Rosstat “very, very sad” and urged Russians to get vaccinated.

“It is the only thing that can help us curb the number of the deaths from the coronavirus,” Peskov said.