Ukraine has stabilised the front line and broken Russia's ability to advance by killing so many of its men, according to Gen Oleksandr Syrskyi.
Making the comments in an interview with the BBC, it marks his first interview since he was dramatically forced from his post in the summer. Syrskyi was appointed Ukraine's commander-in-chief in 2024.
He had previously won praise for defending Kyiv at the start of Russia's full-scale invasion in 2022, and for leading the successful counteroffensive east of Kharkiv in the autumn of that year.
Neither Russia nor Ukraine officially release the numbers of their dead. However, UK intelligence chiefs estimate Russia has lost around half a million men killed in Ukraine since launching its full-scale invasion in 2022.