A senior Ukrainian official dismissed what he depicted as a cynical assertion by Moscow, and said the simplest solution to the situation would be for Russian forces to withdraw from the plant, remove any munitions stored there and demine it.
The Zaporizhzhia nuclear reactor complex, the largest in Europe, was captured by Russia soon after it invaded Ukraine almost six months ago and has come under repeated shelling, with both Moscow and Kyiv trading blame.
Russia says Ukrainian forces are recklessly firing at the plant, but Ukraine says Russia is deliberately using the reactor complex as a base to launch attacks against its population.
Russian defence ministry spokesman Igor Konashenkov told reporters on Thursday that Moscow was taking measures to ensure safety at the complex and denied it had deployed heavy weapons in and around the plant.
However the ministry said a shutdown of the plant may be attempted if Ukrainian forces continued shelling it.
Yevgeny Balitsky, head of the Russian-installed administration in Zaporizhzhia region, said earlier there was a risk that shelling could damage the cooling system of the reactor complex and was quoted as saying the plant was operating with only one unit.
It is not clear how the plant will be shut down, but the ministry said two of the plant's six units may be put into "cold reserve". The plant accounts for one fifth of Ukraine's annual electricity production.
The Russian defence ministry earlier on Thursday accused Ukraine and what it called its "US handlers" of trying to stage a "minor accident" at the plant in southern Ukraine in order to blame Russia.
It said the "provocation" was timed to coincide with a visit to Ukraine by UN chief Guterres on Friday and it may involve a radiation leak.
Reuters could not verify Russia's assertion.
"Russia is worried about the possibility of a disaster at the ZNPP (Zaporizhzhia nuclear power plant). Russia's Ministry of Defence laughs cynically," Mykhailo Podolyak, an adviser to President Volodymyr Zelenskiy, wrote on Twitter.
"There is a solution. You just need to take the (munitions)out of the halls, demine the buildings, release the plant's personnel from cells, stop shelling (the southern city of) Nikopol from (the plant's) territory and leave the station. It's simple, isn't it?"
In a briefing, Igor Kirillov, head of Russia's radioactive, chemical and biological defence forces, said the plant's back-up support systems had been damaged as a result of shelling.
Kirillov presented a slide, showing that in the event of an accident at the plant, radioactive material would cover Germany, Poland and Slovakia.
Guterres, who is set to meet Ukrainian President Volodymyr Zelenskiy later on Thursday, has called for a halt to all fighting near the plant.
