Moscow, Aug 14 : Russian diplomat Mikhail Ulyanov has called on the United Nations to intervene to ensure the safety of the Ukrainian nuclear power plant Zaporizhzhya, which has been subject to shelling for several weeks. It is the task of the UN Secretariat to "give the green light for a visit to the nuclear power plant by experts from the International Atomic Energy Agency (IAEA)," Ulyanov told the Russian state news agency Tass in an interview published on Sunday. The diplomat represents Russia at international organisations in Vienna. The IAEA could then take care of the "modalities of the trip to the troubled region," dpa news agency reported quoting Ulyanov as saying. According to reports, the UN has so far not allowed IAEA chief Rafael Grossi to travel, not only for security reasons, but also because of a dispute over the itinerary. Grossi could travel under Russian protection via the Black Sea peninsula of Crimea, which was annexed by Moscow in 2014, but this would be perceived as an affront by Kiev. "We worked very closely with the organization in May/July and prepared the visit. The UN Secretariat blocked it at the last moment without explaining the reasons," Ulyanov said. Ukraine and Russia have been accusing each other for weeks of shelling Europe's largest nuclear power plant, thereby risking a nuclear disaster. "You cannot send an international team under constant artillery fire. That is the main obstacle," Ulyanov said. Ukraine accuses Russian troops of using the nuclear power plant as a fortress from which to fire on the small towns of Nikopol and Marhanez, which lie on the other bank of the Dnipro reservoir. Russia, on the other hand, claims that Ukraine is shelling the plant with drones, heavy artillery and rocket launchers. /IANS