The latest estimate was that about 21,000 civilian residents of the Ukrainian city of Mariupol had been killed since the start of Russia's invasion, the mayor of the port city said on Tuesday.
In televised comments, Mariupol Mayor Vadym Boichenko said it had been difficult to calculate the exact number of casualties since street fighting had started.
- Russia-Ukraine talks -
Ukrainian presidential adviser Mykhaylo Podolyak said that ongoing talks with Russia to end the war were "extremely difficult" after Moscow accused Ukrainian negotiators of slowing down discussions by changing position on a key issue.
"Negotiations are extremely difficult. The Russian side adheres to its traditional tactics of public pressure on the negotiation process, including through certain public statements," Podolyak said in written comments to reporters.
- Related: Over 4.6m flee war in Ukraine
