A drone armed with a warhead hit the outer shell of Ukraine’s Chernobyl nuclear plant, briefly starting a fire, in an attack Kyiv blamed on Russia.

Investigators from the Security Service of Ukraine (SSU) have opened a criminal case over Russia’s attack on the containment structure over the destroyed Unit No 4 at the Chornobyl Nuclear Power Plant (NPP).

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.