Ukrainian president Volodymyr Zelenskiy has warned Russian soldiers who shoot at Europe's largest nuclear power station or use it as a base to shoot from that they will become a "special target" for Ukrainian forces.
UN Secretary-General Antonio Guterres has called for the establishment of a demilitarised zone at the Zaporizhzhia plant in southern Ukraine amid fears of a nuclear catastrophe over renewed shelling in the past days, for which Russia and Ukraine blame each other.
Mr Zelenskiy, who did not give any details, reiterated that he considered Russia was using the plant, which it captured early in the war but is still being run by Ukrainians, as nuclear blackmail.
"Every Russian soldier who either shoots at the plant, or shoots using the plant as cover, must understand that he becomes a special target for our intelligence agents, for our special services, for our army," he said in an evening address on Saturday.
The Zaporizhzhia plant dominates the south bank of a vast reservoir on the Dnipro River. Ukrainian forces controlling the towns and cities on the opposite bank have come under intense bombardment from the Russian-held side.
Ukrainian presidential adviser Mykhailo Podolyak accused Russia of "hitting the part of the nuclear power plant where the energy that powers the south of Ukraine is generated".
"The goal is to disconnect us from the (plant) and blame the Ukrainian army for this," Mr Podolyak wrote on Twitter.
A foreman who worked at the plant was killed on Sunday by Russian shelling while walking his dog near his home in the city of Enerhodar, Ukraine's state-run nuclear company Energoatom said.
Local Russian-installed official Vladimir Rogov wrote on Telegram that Ukrainian forces had shelled the city and were responsible for the man's death.
The International Atomic Energy Agency, which is seeking to inspect the plant, has warned of a nuclear disaster unless fighting stops. Nuclear experts fear fighting might damage the plant's spent fuel pools or the reactors.
As fighting continued, more ships carrying Ukrainian grain left or prepared to do so as part of a late July deal aimed at easing a global food crisis.
An Ethiopia-bound cargo, the first since Russia's invasion of Ukraine, was getting ready to leave in the coming days, while sources said the first grain ship to leave Ukraine under a UN deal was nearing Syria.
"The world needs the food of Ukraine. This is the beginning of what we hope is normal operations for the hungry people of the world," Marianne Ward, World Food Programme deputy country director, told reporters. The relief agency bought more than 800,000 tonnes of grain in Ukraine last year.
Kyiv has said for weeks it is planning a counteroffensive to recapture Zaporizhzhia and neighbouring Kherson provinces, the largest part of the territory Russia seized after its February 24th invasion and still in Russian hands.
Russia's priority over the past week has likely been to reorient units to strengthen its campaign in southern Ukraine, British military intelligence said on Sunday.
Russian-backed forces of the self-proclaimed Donetsk People's Republic in the eastern region of Donbas continued assaults to the north of Donetsk city, the British Defence Ministry said in its daily intelligence bulletin on Twitter.
Ukraine's military command said early on Sunday that Russian soldiers had continued, unsuccessfully, to attack Ukrainian positions near Avdiivka, which since 2014 has become one of the outposts of Ukrainian forces near Donetsk.
Russia, in a daily briefing, said it had taken control of Udy, a village in the eastern Kharkiv region, which is under continual shelling by Russian forces.
Reuters could not independently verify the battlefield accounts.
Russia calls its invasion of Ukraine a "special military operation" to demilitarise and "denazify" its smaller neighbour. The war has pushed Moscow-Washington relations to a low point, with Russia warning it may sever ties.