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.
There was no count of civilian casualties, he said.
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.
A view shows a street damaged during Ukraine-Russia conflict in the southern port city of Mariupol, Ukraine.
ALEXANDER ERMOCHENKO
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.
"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 US official said.
Ukrainian President Volodymyr Zelenskyy attends a meeting with Prime Minister Boris Johnson at the Munich Security Conference in Germany.
Matt Dunham
Zelenskiy said the military situation in the south and east was "still very difficult," while praising the work of his armed forces.
"The successes of our military on the battlefield are really significant, historically significant. But they are still not enough to clean our land of the occupiers. We will beat them some more," he said in a late-night video address, calling again for allies to send heavier weapons and for an international embargo on Russian oil.
Zelenskiy has appealed to US President Joe Biden for the United States to designate Russia a "state sponsor of terrorism," joining North Korea, Cuba, Iran and Syria, the Washington Post reported, citing people familiar with their conversation.
A White House spokesperson responded by saying, "We will continue to consider all options to increase the pressure on Putin."
Ukrainian Prime Minister Denys Shmyhal and top finance officials will attend International Monetary Fund and World Bank meetings in Washington next week, sources told Reuters.
It will be the first chance for key Ukrainian officials to meet in person with financial officials from advanced economies since Russia's invasion of Ukraine on Feb. 24.