Ukraine's atomic energy agency accused Russia of using Europe's largest nuclear power plant to store weapons and shell the surrounding regions of Nikopol and Dnipro that were hit Saturday.
Petro Kotin, president of Ukrainian nuclear agency Energoatom, called the situation at the Zaporizhzhia nuclear plant "extremely tense" with up to 500 Russian soldiers controlling the plant.
The plant in southeast Ukraine has been under Russian control since the early weeks of Moscow's invasion, though it is still operated by Ukrainian staff.
"The occupiers bring their machinery there, including missile systems, from which they already shell the other side of the river Dnipro and the territory of Nikopol," he said in a Ukrainian television interview broadcast Friday.
On Saturday, Russian missiles struck residential buildings in the city of Nikopol, killing two people, Dnipro regional governor Valentyn Reznichenko said.
In the northeast region around Ukraine's second city of Kharkiv, governor Oleh Synyehubov said an overnight Russian missile attack killed three people in the town of Chuhuiv.
In the central Ukrainian city of Vinnytsia, officials said the death toll rose to 24 from Russian strikes after a woman died of her injuries in hospital Saturday. Ukraine said three children were among the dead.
"Sixty-eight people continue treatment, including four children. Four people are still missing," said Vinnytsia district chief Serhiy Borzov.
Grief outpouring for four-year-old
President Volodymyr Zelensky accused the Russians of aiming to "cause maximum damage to Ukrainian cities."
"I'm urging you, once again: please don't ignore the air raid signals now," he said in his daily address Friday.
Russia claimed the strikes in Vinnytsia — hundreds of kilometers away from frontline fighting — had killed Ukrainian military officials and foreign arms suppliers.
But Ukraine said the dead included four-year-old Liza Dmitrieva, who had Down's syndrome and whose death spurred an outpouring of grief after footage of her final moments alive went viral on social media.
Liza's mother is in a "critical" condition after surgery.
The missile strikes on Vinnytsia were the latest attacks to carry a heavy civilian toll and came less than a week after strikes on Chasiv Yar in the Donetsk region left nearly 50 dead.
Leaning on her cane, Olha Dekanenko walks through the rubble and debris of her home in Kostiantynivka, an industrial town on the frontline in the east, that was heavily damaged in a Russian strike early Saturday.
Dekanenko was asleep when it happened. Her small bedroom overlooks the garden where the rocket landed. She woke up on the ground, covered in a mess of blankets, pillows and stones.
"We're alive, it's a good day," 67-year-old Dekanenko tells AFP with a tired smile.
'Clearing' Donbas town
Moscow invaded Ukraine on February 24 and the conflict has killed thousands of people, destroyed cities and forced millions to flee their homes.
A two-day meeting of finance ministers from the Group of 20 major economies looked for solutions to the food and energy crises caused by the war but the gathering ended Saturday in Indonesia without a joint communique after the conflict divided the global forum.
Observers said the failure to agree on a joint communique would hinder coordinated efforts to solve rising inflation and food shortages.
The heaviest fighting has recently focused on the industrial Donbas region in the east, where grinding trench battles and artillery duels are morphing into a war of attrition.
Britain said Friday the Kremlin "must bear the full responsibility" for the death of a British captive in east Ukraine.
"I am shocked to hear reports of the death of British aid worker Paul Urey while in the custody of a Russian proxy in Ukraine," Foreign Secretary Liz Truss said.
Moscow-backed separatists said Friday they were closing in on their next target, Siversk, after wresting control of sister cities Lysychansk and Sievierodonetsk about 30 kilometers to its east.
Russia's defense ministry spokesman Igor Konashenkov said Saturday strikes targeted Ukrainian soldiers in a brigade that "operated in the Siversk direction."
And Donetsk separatist official Daniil Versonov said rebel fighters were "clearing" eastern districts of Siversk in small groups.
Ukraine has repeatedly urged allies to supply it with advanced, long-range precision artillery systems that would allow it to target Russian forces deeper inside Ukrainian-held territory.
Defence Minister Oleksii Reznikov said Friday that Ukraine had taken delivery of its first batch of sophisticated M270 rocket systems, adding to a growing arsenal of Western-supplied artillery Kyiv says is changing dynamics on the battlefield.