Director general Rafael Grossi said that inspectors would return in the next few days because Ukraine had asked for them to.
NATO doesn’t believe Russia’s claims because it hasn’t given any proof.
Ukraine’s President Volodymyr Zelensky said that this meant that Russia could be planning a similar attack.
So-called “dirty bombs” have radioactive materials in them, like uranium, that get spread through the air when a normal explosive goes off. They don’t need to have highly refined radioactive material like a nuclear bomb, which makes them cheaper and easier to move.
The IAEA (International Atomic Energy Agency) said it had been asked by the Ukrainian government to do “verification activities” at two places it didn’t name. The agency’s inspectors have been to both places on a regular basis, it said.
Mr. Grossi said, “One of these sites was inspected by the IAEA a month ago, and all of our findings were in line with what Ukraine had said in its safeguards declarations.”
“No nuclear activities or materials that hadn’t been reported were found there,” he said.
What is a ‘dirty bomb’?
Russia’s state-run news agency, RIA Novosti, said that the Eastern Mineral Enrichment Plant in central Dnipropetrovsk region and the Institute for Nuclear Research in Kyiv were at the centre of the alleged Ukrainian operation.
On Tuesday, Moscow is likely to bring up the claim again at a meeting of the UN Security Council. In a letter to UN Secretary-General Antonio Guterres, the Russian representative to the council, Vassily Nebenzia, said that his country would “consider the use of the dirty bomb by the Kyiv regime as an act of nuclear terrorism.”
“Our Ministry of Defense has also heard that this provocation could happen with the help of Western countries,” Mr. Nebenzia wrote in his letter.
The accusations made by Sergei Shoigu, who is Moscow’s minister of defence, have been shot down by Ukraine and its Western allies. In a joint statement released on Monday, the foreign ministers of the US, UK, and France called the claims “obviously false” and said that the “world would see through any attempt to use this allegation as a reason to escalate.”
In his nightly address on Monday, President Zelensky said, “If Russia calls and says that Ukraine is supposedly getting ready for something, it means only one thing: Russia has already gotten ready for all of this.”
Western intelligence officials have been very clear that there is no evidence that Russia is planning to use dirty bombs or other nuclear weapons.
The Russians are making these claims as Ukrainian forces keep making gains in the southern part of the Kherson region. Kyiv’s forces started a counterattack in the area in August, and they have been slowly moving toward Kherson city, which is the regional capital.
In the past few days, officials put in place by Moscow have left the city and asked people to leave across the Dnieper river into Russian-controlled territory.
But the head of Ukraine’s military intelligence, Kyrylo Budanov, told state media that Russian troops in the area were getting ready to defend the city instead of leaving.
“They are making it look like everything is lost. At the same time, though, they are bringing in new military units and getting ready to defend the streets of Kherson “Mr Budanov said.
Regional authorities have said that some men who chose to stay in the city could join local militias to protect it. This has caused people to worry that Moscow could force men to join the military. The Geneva convention says that doing these things would be a war crime.
During their invasion, Russian forces have only been able to take Kherson, a major city and regional capital in Ukraine.