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.

“Last night, a Russian attack drone with a high-explosive warhead struck the shelter protecting the world from radiation at the destroyed 4th power unit of the Chornobyl Nuclear Power Plant,” Ukrainian president Volodymyr Zelenskyy said of the attack.

A drone armed with a warhead hit the outer protective shell of Ukraine's Chernobyl nuclear plant early Friday, damaging the structure and briefly starting a fire, in an attack Kyiv blamed on Russia. The Kremlin denied it was responsible.