Ukraine's Sievierodonetsk falls to Russia after one of war's bloodiest fights

Russian forces fully occupied the eastern Ukrainian city of Sievierodonetsk on Saturday.

Russian forces fully occupied the eastern Ukrainian city of Sievierodonetsk on Saturday, both sides said, confirming Kyiv's biggest battlefield setback for more than a month following weeks of some of the war's bloodiest fighting.

Ukraine called its retreat from the city a "tactical withdrawal" to fight from higher ground in Lysychansk on the opposite bank of the Siverskyi Donets river. Pro-Russian separatists said Moscow's forces were now attacking Lysychansk.

The fall of Sievierodonetsk - once home to more than 100,000 people but now a wasteland - was Russia's biggest victory since capturing the port of Mariupol last month. It transforms the battlefield in the east after weeks in which Moscow's huge advantage in firepower had yielded only slow gains.

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Russia will now seek to press on and seize more ground on the opposite bank, while Ukraine will hope that the price Moscow paid to capture the ruins of the small city will leave Russia's forces vulnerable to counterattack.

President Volodymyr Zelenskyy vowed in a video address that Ukraine would win back the cities it lost, including Sievierodonetsk. But acknowledging the war's emotional toll, he said: "We don't have a sense of how long it will last, how many more blows, losses and efforts will be needed before we see victory is on the horizon."

"The city is now under the full occupation of Russia," Sievierodonetsk Mayor Oleksandr Stryuk said on national television. "They are trying to establish their own order, as far as I know they have appointed some kind of commandant."