Swine flu has killed nearly 40 people in Russia since last month, with one of the cases reported in the capital, Moscow.
According to official data gathered by the AFP, at least 39 people have died of the disease.
“Eleven people died from the virus and nearly 50 schools have declared a quarantine,” health authorities in the southern region of Volgograd told state news agency RIA Novosti on Friday.
Six fatal swine flu-related deaths have also been recorded in the southern region of Rostov and five deaths were reported in Saint Petersburg.
These latest cases follow the deaths of four adults and one child from the virus in the North Caucasus region of Dagestan, and the deaths of two infected patients in Yekaterinburg in the Urals and the southern region of Adygea.
Swine flu fatalities have also been reported in the Kostroma, Tambov and Kaliningrad regions, among others.
Anna Popova, a senior doctor in the country, assured the public that “all necessary measures” were being taken to prevent the spread of the deadly virus in Russia.
In neighboring Armenia, 18 people have died of swine flu since the start of 2016, the South Caucasus country’s health ministry said this week.
In nearby country Georgia, three deadly cases of the virus have been reported.
A major outbreak of the H1N1 virus sparked a World Health Organization pandemic alert in June 2009, after the virus emerged from Mexico and the United States.
The outbreak killed about 18,500 people in 214 countries. The alert was lifted in August 2010.