Almost 13,000 Ukrainian soldiers have died since Russia's invasion, an aide of President Volodymyr Zelensky has claimed.
Mykhailo Podolyak, who advises the Ukrainian President estimates that between 10,000 and 13,000 troops have lost their lives.
None of the two countries involved in the war give figures for the casualties of their respective countries and Mr Podolyak's remarks have not been confirmed by Ukraine.
