For several months, Moscow and kyiv have accused each other of bombardments on the site, close to the front line.
The head of the International Atomic Energy Agency (IAEA) Rafael Grossi estimated that the weekend strikes - "a good dozen" - were "absolutely deliberate, targeted", without attributing responsibility to Russian or Ukrainian forces, - and judged the situation "serious", in an interview with the French channel BFMTV.
For the Russian Ministry of Defence, "the kyiv regime does not cease provocations in order to create the threat of a disaster at the Zaporizhia nuclear power plant".
On Saturday and Sunday, Ukrainian forces fired more than 20 "large caliber shells" at the plant, the ministry statement said.
These notably exploded between energy blocks number 4 and 5 and targeted the roof of a "special building" located near these blocks, according to the same source.
This "special building" houses a nuclear fuel depot, said an official of the Russian nuclear electricity producer Rosenergoatom, Renat Kartchaa, quoted by the Russian official agency TASS.
Despite these bombings, "the level of radiation in the area of the power plant remains within the norm", underlines the press release from the Russian Ministry of Defense.
For its part, the Ukrainian nuclear agency accused Russia of having bombed the site of the plant.
"This morning of November 20, 2022, following heavy Russian bombing, at least 12 strikes were recorded at the site of the Zaporizhia nuclear power plant," Energoatom said, accusing the Russians of "once again organizing a nuclear blackmail and put the whole world in danger".
"There are those who consider a nuclear power plant to be a legitimate military target, which is unbelievable," the IAEA director general said indignantly.
- "Stop this madness" -
“Whoever it is, stop this madness!”, urged Mr. Grossi, insisting: “People doing this know where they are hitting. It is absolutely deliberate, targeted”.
"The plant is on the front line, there are military activities that are very difficult to identify, there are Russian personnel and Ukrainian personnel in operation," said Mr. Grossi.
The IAEA, which has two on-site inspectors at the plant, is carrying out an assessment. "There was damage in quite delicate places", estimated Mr. Grossi, specifying that the reactors had not been affected but "rather the zone where the fresh and spent fuels are".
"We expect to be able to make an inventory tomorrow (Monday) morning very early," he added, adding that the inspectors had not been able to go out on Sunday because the situation was too dangerous.
French President Emmanuel Macron spoke to the head of the IAEA on Sunday about the situation at the Zaporizhia plant and "will probably speak" to Ukrainian President Volodymyr Zelensky, according to the French presidency.
Russia, which has been leading an offensive in Ukraine since February 24, is militarily occupying the territory of the plant. Russian President Vladimir Putin has demanded its annexation, as well as that of four Ukrainian regions.