More than 20 weeks since Russia invaded its neighbor, leading to thousands of deaths and millions of displaced Ukrainians, the war-ravaged nation's President Volodymyr Zelensky blamed Moscow for seeking to cause maximum damage, but pledged that Ukraine will "endure" in the conflict.

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.

Russian missiles fired Saturday struck residential buildings in the city of Nikopol, killing two people, Dnipro regional governor Valentin Reznichenko said.

In the northeast region around Ukraine's second city of Kharkiv, governor Oleg Synegubov said an overnight Russian missile attack killed three in the town of Chuguiv.

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 Sergiy Borzov.

- 'Brutal blows' -

Zelensky angrily accused the Russians of bombing campaigns that cause "maximum damage" to Ukrainian cities, and urged citizens to heed air raid signals.

In a Saturday evening address, Zelensky said Ukraine has "withstood Russia's brutal blows" and managed to take back some of the territory it lost since the start of the war, and will eventually recapture more occupied land.

"We will endure. We will win," he said, and "rebuild our lives."

Russia claimed the strikes in Vinnytsia -- hundreds of kilometres 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 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, Olga Dekanenko walks through the rubble and debris of her home in Konstantinovka, 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 -

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.

The failure to agree on a joint communique will hinder coordinated efforts to solve rising inflation and food shortages.

Canada meanwhile blasted Moscow's participation in the G20 meeting as "absurd," with Finance Minister Chrystia Freeland saying from Bali that Russia's presence "was like inviting an arsonist to a meeting of firefighters."

In Ukraine, 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.

Moscow-backed separatists said Friday they were closing in on their next target, Siversk, after wresting control of sister cities Lysychansk and Severodonetsk about 30 kilometres (18 miles) to its east.

Russia's defence ministry spokesman Igor Konashenkov said Saturday strikes targeted Ukrainian soldiers in a brigade that it said 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.

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