"The situation in Kurakhove is really quite difficult right now, because a significant part of the city has been destroyed," Khortytsia group of forces spokesperson Viktor Trehubov said on national television Jan.

Russia said on Monday its forces had made important gains in eastern Ukraine while continuing to fend off a new Ukrainian offensive inside the Kursk region of western Russia, where a second day of fierce fighting was under way.

Russia and Ukraine traded attacks in the Kursk region this week as Moscow looks to continue clawing back its territory. Meanwhile, Russian forces appear to have taken the eastern city of Kurakhove but failed to encircle the Ukrainian forces there.