Russia claims to have taken control of Vuhledar, a transport hub in the eastern Ukrainian region of Donetsk, after a period of fierce fighting in the area.
Defense ministry officials said on Thursday troops had “liberated” the city.
Russian media outlets say control of the area will cut supplies to Ukrainian forces, who are now solidifying their defenses after allowing a unit to withdraw from Vuhledar.
Ukrainian President Volodymyr Zelenskyy said on Thursday the move was aimed at saving the lives of the soldiers.
The country’s top commander Oleksandr Syrskyi says he has made a number of decisions aimed at strengthening defenses.
Ukrainian forces have withdrawn from key positions in Donetsk this year. Russian troops are likely to step up their offensive and attempt to seize the entire region.