A Russian drone struck the former nuclear power plant at Chernobyl in an attack overnight into Friday, Ukrainian President Volodymyr Zelensky has said. The strike hit the concrete shelter that covers the plant’s destroyed former fourth power unit,

President Volodymyr Zelensky of Ukraine called the damage “significant” but said there were no signs of radiation leaks. A Kremlin spokesman denied that Russia had carried out the strike.

Ukrainian President Volodymyr Zelenskiy said on Friday that a Russian drone had caused significant damage to the radiation containment shelter at the disused Chornobyl nuclear power plant overnight.