The UN’s nuclear watchdog has issued a statement to try to calm concerns that a power blackout at the defunct Chernobyl nuclear plant could send radioactive particles into the air across Europe. Earlier, Ukraine’s state nuclear company Energoatom said Russian forces cut off the site’s power supply, making it impossible to cool deposits of spent nuclear fuel there, which it claimed could lead to the spent fuel heating up and sending a “radioactive cloud” across Europe. That claim was repeated by Ukraine’s foreign minister, who said backup generators at the plant would run out of power in 48 hours, making “radiation leaks imminent.” However, in a statement, the IAEA said the cut power line “does not provide power to safety-related equipment,” and added: “Due to time elapsed since the 1986 Chornobyl accident, the heat load of the spent fuel storage pool and the volume of cooling water contained in the pool is sufficient to maintain effective heat removal without the need for electrical supply.”

Russian forces have 48 hours of power in back-up generators at the defunct Chernobyl nuclear plant left before a blackout could send radioactive particles into the air over Europe, Ukraine has warned.

The site of the world’s worst ever nuclear disaster in 1986 is once again the cause of concern across Europe on Wednesday after Ukrainian officials accused the invading Russian forces of severing the high-voltage line that supplies power to the mothballed plant. The plant is now relying on back-up generators that are only designed to last for two days.

That could be extremely bad news, according to the Ukrainian government and its state energy companies, who say a lack of power would make it impossible to cool 20,000 spent nuclear fuel assemblies at the site.

Ukraine’s state-run nuclear company Energoatom said in a Telegram post Wednesday that if that spent nuclear fuel warms up, it could lead to “the release of radioactive substances into the environment. The radioactive cloud could be carried by wind to other regions of Ukraine, Belarus, Russia, and Europe.” The International Atomic Energy Agency said in an earlier statement that it had lost contact with the Chernobyl site.