Russian forces have ramped up a winter assault in eastern Ukraine, bringing tens of thousands of freshly mobilized troops to the battlefield, while Kyiv expected Moscow to broaden its offensive as towns in the northeast and south came under fire.

Ukraine's military said on Tuesday that 1,030 Russian troops were killed over 24 hours, the highest daily toll of the war. The figure could not be independently verified, and Russia has also claimed to have killed large numbers of Ukrainian troops in recent weeks. For its part, Russia said it had inflicted 6,500 Ukrainian casualties in the month of January.

Ukraine national security chief Oleksiy Danilov said in an interview on Tuesday that the Kremlin is expected to target the northeastern Kharkiv or southern Zaporizhzhia regions in a new thrust.