Nearly 5,000 people killed in Mariupol, more than 100 war deaths in Kyiv - mayors

Nearly 5,000 people have been killed in the southern Ukrainian city of Mariupol since Russian forces laid siege to it, a spokesperson for the city mayor said on Monday.

The spokesperson quoted data from the mayor's office that said about 90% of buildings in Mariupol had been damaged and about 40% had been destroyed.

In the Ukrainian capital Kyiv, on the other hand, there have been more than 100 deaths since Russia's invasion of its neighbour, the city's mayor Vitali Klitschko said on Monday.

In an address to city councillors of Florence, which is twinned with Kyiv, Klitschko said more than 20 corpses could not be identified and four of the victims were children, while another 16 injured children are in hospital.

"The cities around Kyiv have seen numerous battles ... on the roads we see many corpses and pieces of human corpses," Klitschko said according an Italian interpreter.

The former world heavyweight boxing champion said 82 multi-storey buildings in Kyiv had been destroyed by Russian attacks and it was impossible to know the true death toll in the city.

Ukraine and Russia were preparing on Monday for the first face-to-face peace talks in more than two weeks, but a senior U.S. official said Russian President Vladimir Putin did not appear ready to make compromises to end the war.

Kyiv has so far been spared the kind of destruction wrought on southern cities such as Mariupol, where more than 5,000 people have died, according its mayor.

Klitschko said the capture of Kyiv had been among Russia's "main plans" at the start of its invasion, but it had been blocked so far by Ukraine's resistance.

"We have destroyed the myth of the invincible Russian army. We are resisting against the aggression of one of the strongest armies in the world and have succeeded in making them change their goals," he said.

Klitschko appealed to Italy's politicians to maintain sanctions against Moscow and not to believe what he said was Russian propaganda about the war.

"The destabilisation of our country can cause repercussions in all the other European countries," Klitschko said.

Without citing evidence, he said Russian imperialism would not stop at Ukraine, warning that if it was not stopped now it may target Poland, the Czech Republic and Hungary.

Russia calls its actions in Ukraine a "special military operation".