Amid concerns about potential attacks by Russia during the upcoming winter season, Ukraine’s power grid faced pressure Monday from a snowstorm that knocked out electricity to more than two thousand towns and villages.

Ukraine’s interior ministry said towns in 16 different regions were cut off from the power grid as a result of the storm, with areas in central and southern Ukraine hardest hit.

Ukrainian President Volodymyr Zelenskyy used part of his nightly address Sunday to thank those working to restore services. He also said that during such difficult conditions, Ukrainians should be especially grateful for military members who are battling Russia’s invasion.

Russian forces repeatedly struck Ukrainian power grid infrastructure during the last winter season, causing widespread blackouts and forcing Ukraine to scramble to make repairs.

Also Monday, Britain’s defense ministry said in its latest assessment that Russia has likely experienced its highest casualty rates of the war during the past six weeks.

The British ministry cited data from Ukraine’s military, which said there were an average of 931 Russian casualties per day in November, exceeding the previous high of 776 per day in March.

“Although Defence Intelligence cannot verify the methodology, taken as a total including both killed and wounded, the figures are plausible,” the British ministry said.

Some information for this story came from The Associated Press, Agence France-Presse and Reuters.