Russia has accused Ukraine of planning a "provocation" at the Zaporizhzhia nuclear power plant, which is under Russian control.
In a statement on Thursday, Russia's Defense Ministry said that Kiev would carry out its plan during UN Secretary General Antonio Guterres' visit, which is due to take place on August 19, without providing any evidence.
The ministry also stressed that there were no Russian heavy weapons at the nuclear reactor complex, located near the city of Enerhodar in southeastern Ukraine, or in nearby districts.
Zaporizhzhia is the largest nuclear power plant in Europe and among the 10 largest in the world. Russian forces seized the plant soon after Moscow launched its ongoing military offensive in the ex-Soviet country on February 24. Ukraine accuses Russia of storing heavy weapons in the plant.
Ukraine's top nuclear official has said that 500 Russian soldiers and 50 pieces of heavy machinery, including tanks, trucks, and armored infantry vehicles, are at the site.
The plant has come under fire repeatedly in recent weeks. Both Ukraine and Russia accuse each other of targeting the facility.
Last Thursday, the UN nuclear watchdog called for officials to visit the Zaporizhzhia power plant amid fresh escalation in the area and warnings of the "catastrophic consequences" of continued fighting near the atomic plant.
At an emergency meeting of the UN Security Council on Thursday night, the Agency's chief, Rafael Grossi, warned that parts of the nuclear plant that had been knocked out due to recent attacks risked an "unacceptable" potential radiation leak.
Russia has also requested an urgent meeting of the UN Security Council concerning Ukraine's continuous attacks on the Zaporizhzhia nuclear power plant, as both sides continue to blame each other for repeated shelling of the site.
In a tweet last Wednesday, Russia's Ambassador to the International Atomic Energy Agency (IAEA) Mikhail Ulyanov warned that the shelling of the nuclear plant could result in a "large-scale catastrophe" in Europe.