Ukraine says renewed Russian shelling has damaged three radiation sensors and injured a worker at the Zaporizhzhia power plant, the second hit in consecutive days on Europe's largest nuclear facility.
Ukrainian President Volodymyr Zelenskyy called the shelling "Russian nuclear terror" that warranted more international sanctions, this time on Moscow's nuclear sector.
"There is no such nation in the world that could feel safe when a terrorist state fires at a nuclear plant," Mr Zelenskyy said in a televised address.
However, the Russian-installed authority of the area said it was Ukraine that hit the site, damaging administrative buildings and an area near a storage facility.
Neither account could be independently verified.
Events at the Zaporizhzhia site — where Kyiv had previously alleged Russia hit a power line on Friday — have alarmed the world.
According to the International Atomic Energy Agency, it "underlines the very real risk of a nuclear disaster".
Elsewhere, a deal to unblock Ukraine's food exports and ease global shortages saw another four ships sail out of Ukrainian Black Sea ports.
The four outgoing ships are carrying nearly 170,000 tonnes of corn and other food and are sailing under a deal brokered by the United Nations and Turkey to help ease soaring global food prices resulting from the war.
Before Moscow's invasion, which Russian President Vladimir Putin calls a "special military operation", Russia and Ukraine together accounted for nearly one-third of global wheat exports.
The disruption since then has threatened famine in some parts of the world.
Battle for Donbas continues
Russian troops are trying to gain full control of the Donbas region in eastern Ukraine where pro-Moscow separatists seized territory after the Kremlin annexed Crimea to the south in 2014.
Russian forces stepped up their attacks north and north-west of the city of Donetsk in the region, according to Ukraine's military, reporting that the Russians attacked Ukrainian positions near the heavily fortified settlements of Piski and Avdiivka, as well as shelling other locations in the Donetsk region.
In addition to tightening its grip on the Donbas region, Russia is entrenching its position in southern Ukraine, where it has gathered troops in a bid to prevent a potential counteroffensive near Kherson.
As the fighting rages, Russians installed in the wake of Moscow's invasion have toyed with the idea of joining Ukraine's occupied territory to Russia. Last month, a senior pro-Russian official said a referendum on such a move was likely to be held "towards next year".
In his video address, Mr Zelenskyy said any "pseudo-referendums" on occupied areas of his country joining Russia would eliminate the possibility of talks between Moscow and Kyiv or its allies.
"They will close for themselves any chance of talks with Ukraine and the free world, which the Russian side will clearly need at some point," Mr Zelenskyy said.
Meanwhile, Ukraine's chief war-crimes prosecutor said almost 26,000 suspected war crimes committed since the invasion were being investigated, with 135 people charged, of whom 15 were in custody. Russia denies targeting civilians.
Shelling and missile strikes were reported overnight in the Ukrainian city of Kharkiv and around military sites in the western region of Vinnytsia, among other places, Ukrainian authorities said. There was no immediate word on casualties.
ABC/wires
