The UN nuclear energy watchdog has said the forces behind the shelling of Ukraine’s Zaporizhzhia power plant are “playing with fire”, after a series of explosions shook the facility. The International Atomic Energy Agency (IAEA), which has experts based at Zaporizhzhia, reported on Sunday that powerful explosions had shaken the area on Saturday night and Sunday. It said its on-site experts saw some of the explosions from their windows. It reported more than a dozen blasts from apparent shelling, with damage to some buildings, systems and equipment, but “none so far critical for nuclear safety”. The head of the IAEA, Rafael Grossi, said the news was extremely disturbing and he called the explosions completely unacceptable. “Whoever is behind this, it must stop immediately. As I have said many times before, you’re playing with fire,” he said. According to the IAEA Twitter account, Grossi renewed his appeal to Ukraine and Russia to agree and implement a nuclear safety and security zone around the plant as soon as possible. Zaporizhzhia, in south-east Ukraine, is Europe’s largest nuclear power station and has been under Russian control since March, although its Ukrainian staff remain in place to run the facility. It has faced repeated shelling, raising fears of a nuclear disaster. Moscow and Kyiv have blamed each other for the attacks. The plant’s six Soviet-designed water-cooled reactors are currently shut down, but there is a risk that nuclear fuel could overheat if the power that drives the cooling systems is shut. Shelling has frequently damaged the plant’s power supply. Russian officials claimed that Ukrainian forces were behind the latest attacks. “They are shelling not only yesterday but also today, they are shelling even now,” an adviser to the head of Russia’s nuclear power operator Rosenergoatom, Renat Karchaa, told the Russian state news agency Tass. He said there had been 15 aerial strikes, including one that hit a storage facility. Soon after the Russian accusations, Ukraine’s nuclear energy agency, Energoatom, said Russia was responsible for the shelling, which it said had resulted in 12 hits to Zaporizhzhia’s infrastructure. The company said on Telegram that the list of damaged equipment indicated that the attackers “targeted and disabled exactly the infrastructure that was necessary for the restart of 5th and 6th power units” and the restoration of power production for Ukrainian needs. Ukraine faces a collapse in its electricity supply after a relentless Russian bombing campaign targeted at power infrastructure. Ukraine’s president, Volodymyr Zelenskiy, has previously called for all troops to leave the plant so that it is under full control of Ukrainian nuclear workers. His government has called the attacks on the plant false-flag operations by Russia. Elsewhere in the Zaporizhzhia region, Russian forces shelled civilian infrastructure in about a dozen communities, destroying 30 homes, the Ukrainian presidential office said on Sunday. Ukraine’s defence ministry published figures claiming that 84,210 Russian soldiers had been “eliminated” since the war began, including 330 in the last 24 hours. Ukraine also claimed Russia had lost 2,886 tanks, 5,817 armoured vehicles and 278 military jets. Separately, Ukraine’s prosecutor general’s office said at least 437 Ukrainian children have been killed and more than 837 injured as a result of Russia’s invasion. Ukraine and Russia decline to publish their own military casualty figures, but earlier this month a senior US general estimated there had been “well over 100,000 Russian soldiers killed and wounded”, and a similar number on the Ukrainian side. Meanwhile, Ukraine promised to investigate footage that is said to show its forces killing Russian troops. Moscow has said videos circulating on social media show Ukrainian soldiers killing Russian soldiers as they tried to surrender. The Ukrainian deputy prime minister Olha Stefanishyna said Ukrainian authorities would investigate the footage but that it was “very unlikely” the clips showed what Russia claimed, Associated Press reported. The UN’s human rights monitoring mission in Ukraine has called for further investigation, which Stefanishyna said Ukraine had “no problem” with. On Sunday, a key adviser to the Ukrainian presidency said negotiating with Russia would be “capitulation”. Mykhailo Podolyak said attempts by the west to urge Ukraine to negotiate with Moscow were “bizarre” given the series of major military victories achieved by Kyiv. “Any conspiracy theories about ‘surrender’ or west’s secret negotiations with Putin do not take into account ‘small detail’. Ukrainians,” he tweeted. “Ukraine will not kneel to Russians. It is not a matter of politics. It is a matter of our existence.” His statement follows recent US media reports that some senior US officials have privately told Kyiv to be open to negotiations with Russia.