Shelling has resumed around Ukraine's huge nuclear power plant.
Russian and Ukrainian officials blamed each other.
The attacks Wednesday come a day after the U.N. atomic watchdog agency pressed for the warring sides to carve out a safe zone at the plant to prevent a catastrophe.
A Ukrainian regional governor said Russians fired on a city on the opposite bank of the Dnipro River from the plant.
Russian authorities said the city where the power plant is located is in a blackout because Ukrainian shelling damaged a power substation.
In the east and south, Ukrainian officials reported progress in their counter offensive.