"As a result of the strikes, several nuclear reactors at two plants were automatically disabled. These consequences were calculated, and the enemy knew exactly what it was doing," Zelensky said in an address to the nation.

Russia and Ukraine have traded blame for attacks near several nuclear plants in Ukraine since Moscow's forces began their invasion in February.

Kyiv has said that Russian authorities have detained dozens of staff at Europe's largest atomic facility in Zaporizhzhia, endangering operations and raising concerns of a nuclear disaster.

Zelensky also said that power was restored to eight million Ukraine consumers after blackouts across the country following the latest wave of Russian strikes.

"About 10 million Ukrainians were disconnected after the terrorist attack. Supply to eight million consumers has already been restored. Power engineers and repairmen will work all night," Zelensky wrote on Twitter.

Presidential officials said earlier that more than seven million households had been left without electricity after the attacks that targeted Ukraine's power grid.

The presidency later reported that more and more regions and cities were back online following successful completion of repair work.