Moscow, Aug 16 : The United Nations rejected Russian accusations that it is preventing a visit by nuclear experts to the Zaporizhzhya plant in Ukraine, amid reports of more shelling and explosions there on Monday. Ukraine and Russia have been accusing each other for weeks of firing on Europe's largest nuclear power plant, potentially provoking a nuclear catastrophe. The southern Ukrainian site is occupied by Kremlin troops and Russian Defence Minister Sergei Shoigu discussed the situation in a phone call with UN Secretary General Antonio Guterres on Monday, dpa news agency reported. Speaking in New York, UN spokesman Stephane Dujarric said it was "just not the case" that its executive arm was delaying a trip by International Atomic Energy Agency (IAEA) personnel. "The UN Secretariat has no authority to block or cancel" the visit, he said, adding that the Vienna-based IAEA nuclear body acts independently of the UN. The UN has "the security, the logistics capacity" in Ukraine to support the visit by IAEA inspectors to Zaporizhzhya, Dujarric said. "But there needs to be an agreement with Russia and Ukraine," he added. There have been disagreements over a number of issues, including what a travel route for IAEA inspectors might look like. Ukraine would not allow a mission exclusively through Russian-occupied territory - such as via Crimea or by other means across the Russian-Ukrainian border. Moscow-installed officials rejected calls for Russian forces to withdraw from the plant and instead proposed a ceasefire for the embattled area. "The leadership of the United Nations and the chief diplomat of the EU should not be talking about demilitarization, but about introducing a ceasefire," Vladimir Rogov, a representative of the Russian occupation authorities in Enerhodar, told Russia's state news agency Ria Novosti. On Sunday, 42 countries including the US, European Union nations and Japan demanded that Russia hand the plant back to Ukraine. A civilian died and two others were injured near the site on Sunday and on Monday, Rogov said on Telegram that locations near the plant in the town of Enerhodar were shelled 25 times with heavy artillery. According to Dmytro Orlov, the Ukrainian mayor who fled Enerhodar after the Russian forces seized the area early in the war, said explosions could be heard from the town. Fighting continued elsewhere, with Russia's military saying it has killed more than 100 "foreign mercenaries" in attacks during the past 24 hours that also left more than 50 wounded in the eastern Kharkiv region, according to officials. Those killed included Germans and Poles, Russian Defence Ministry spokesperson Igor Konashenkov said. The figures could not be independently verified. The Russian army attacked industrial buildings and infrastructure with missiles, Kharkiv governor Oleh Syniehubov said, though he made no mention of casualties. Russian spokesman Konashenkov also said Moscow's forces had attacked Kherson in the south and Donetsk in the east, killing more than 420 Ukrainian soldiers. He also said a Ukrainian command post near Bakhmut, a strategically important town in the Donetsk region, had also been shelled. Russian President Vladimir Putin recognised the Ukrainian regions of Donetsk and Luhansk in the area known as the Donbass as independent states in February despite international protests, and then launched the war. Putin on Monday reaffirmed the goal of completely capturing the Donbass, where Russian separatists had been fighting for years before his invasion. The Kremlin leader told international guests at an annual military forum near Moscow that the Russian army is fulfilling its tasks in the so-called "People's Republics of Donetsk and Luhansk". While Ukraine accuses Russia of serious war crimes and a bloody occupation policy, Putin once again said "the soil of the Donbass is being liberated step by step" from Ukrainian nationalists. In London, British defence analysts said Russian planning for a referendum in the Donetsk region is at an advanced stage. The Ukrainian general staff meanwhile said Ukrainian fighters repelled Russian attacks on the towns of Soledar and Bakhmut. The generals said Kiev's forces also fought off attacks north of the city of Sloviansk and near Vuhledar. The information could not be independently verified. The situation was particularly tense in the Kherson region, where Kiev's troops are trying to recapture ground, the Ukrainian General Staff added. The Ukrainian parliament has again extended martial law and a general mobilization, which have been in force since February 24. The decrees, which include an exit ban for men of conscript age between 18 and 60, will now apply up to and including November 21. It is the second extension since the Russian invasion. Martial law gives the military expanded rights and restricts civil liberties such as the right to demonstrate. Experts see the extension as an indicator of how long Kiev expects fighting to continue. /IANS