Ukraine's President Volodymyr Zelenskiy said about 2,500 to 3,000 Ukrainian troops have been killed in seven weeks of war with Russia and about 10,000 have been injured, Reuters reported.
There was no count of civilian casualties, he told CNN on Friday.
He said 19,000 to 20,000 Russian soldiers had been killed in the war, now in its eighth week. Moscow said last month that 1,351 Russian soldiers had been killed and 3,825 wounded.
Reuters could not independently verify either side's numbers.
Fighting was intense in Mariupol as Ukraine said it was trying to break Russia's siege of the southeastern port city. Home to 400,000 people before Russia's invasion, Mariupol has been reduced to rubble. Thousands of civilians have died and tens of thousands remain trapped. read more
"The situation in Mariupol is difficult and hard. Fighting is happening right now. The Russian army is constantly calling on additional units to storm the city," defence ministry spokesperson Oleksandr Motuzyanyk told a briefing. He said the Russians have not completely captured it.
Russia said it struck what it described as a factory on the outskirts of the capital Kyiv that made and repaired anti-ship missiles, after the sinking on Thursday of the Moskva, the flagship of Moscow's Black Sea fleet.
Ukraine said one of its missiles had caused the Moskva to sink, a powerful symbol of its resistance to a better-armed foe. Moscow said the ship sank while being towed in stormy seas after a fire caused by an explosion of ammunition and that more than 500 sailors were evacuated.
The United States believes the Moskva was hit by two Ukrainian missiles and that there were Russian casualties, although numbers were unclear, a senior U.S. official said.
None of the assessments could be independently verified.
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