After months spent occupying a swathe of territory in Russia in the wake of a daring summer assault, Volodymyr Zelensky has claimed that Ukraine is now engaged against a force of 50,000 troops amassed by Vladimir Putin in the border Kursk region.

Russia attacked the Ukrainian capital Kyiv with a sophisticated combination of missiles and drones for the first time in 73 days on Wednesday, authorities reported, as the Pentagon said most of the North Korean troops sent to help Moscow’s war effort are fighting to drive Ukraine’s army off Russian soil in the Kursk border region.

"Today I can confirm that over 10,000 (North Korean) soldiers have been sent to eastern Russia, and most of them have moved to the far western Kursk Oblast, where they have begun engaging in combat operations with Russian forces,