The number of new coronavirus infections has risen in the Russian city of St Petersburg, ahead of Friday's European Championship quarter-final match.
On Sunday, the authorities in the port city reported almost 1,300 new cases within one day, 50 more than the previous day. There were again more than 100 deaths within 24 hours.
Nationwide, the authorities said there were 21,600 new infections. The worst hit place is Moscow, where there were 6,700 new cases and 114 deaths, the highest number since the beginning of the pandemic, the Interfax news agency reported.
Moscow Mayor Sergei Sobyanin threatened a lockdown on state television. Referring to the rapid spread of the Delta variant, he said: "To solve this problem fundamentally, you have to get vaccinated or go into a lockdown."
Moscow had reopened its European Championship fan zone on Saturday after a shutdown. Numbers have been rising rapidly in Russia since the beginning of June.
The Republic of Buryatia on Lake Baikal in Siberia has already become the first region in Russia to impose a two-week quarantine. Supermarkets and pharmacies are to remain open.
The authorities justified the step with a high coronavirus mortality rate. In addition, there are not enough doctors and hospital beds for patients.
2,000 hospitalized every day
In Moscow, according to Sobyanin, 2,000 new patients with an infection are brought to hospital every day. There are now only 5,000 free beds.
According to the mayor, 86,000 people a day are now registering for a Covid-19 vaccination. Moscow is Europe's largest city, with an estimated population of 12 million.
In the face of widespread vaccination skepticism, several regions in Russia have made vaccination compulsory for certain professions.
Up to 100 people reportedly demonstrated against this in Moscow on Saturday. According to human rights activists, at least eight people were temporarily taken into police custody.
