Ukrainian President Volodymyr Zelensky said on Monday that Russia had suffered heavy losses during five months of fighting against Ukrainian forces in Russia's southern Kursk region, with nearly 15,000 soldiers killed.
"During the Kursk operation, the enemy has already lost 38,000 of its own soldiers in this direction, while nearly 15,000 of those losses are irreversible," Zelensky said in a video speech on Monday.
Zelensky did not provide evidence when he spoke about Russia's losses in this region.
Ukraine launched a major incursion into the Kursk region in August and took control of parts of Russian territory, although the Russian military says it has managed to regain control of most of it.
Ukraine said it launched a new offensive in the region on Sunday, but gave few details.
Some Western countries and Ukraine say more than 11,000 North Korean troops are fighting alongside Russian forces in Kursk.
Russia has neither admitted nor denied the presence of North Korean troops.
Russia's Defense Ministry said on Monday it had halted the advance of Ukrainian forces and destroyed its main forces near the town of Berdin, close to a road leading northeast to the city of Kursk.
The ministry also said Russian forces have made significant advances in eastern Ukraine, including capturing the town of Kurahova.
Ukrainian President Zelensky did not mention Kurahov in his speech. He said that Ukrainian forces have created a security zone in the Kursk region, where Russia has transferred powerful military units. According to him, this has made it impossible for Moscow to deploy those forces in key areas of the front line in eastern Ukraine./REL (A2 Televizion)