“Look, maybe yesterday it was bluff. Now, it could be a reality,” Zelenskiy, who had previously played down such warnings as nuclear blackmail, told CBS News on Sunday.

“I don’t think he’s bluffing,” Zelenskiy added.

The Ukrainian president said Russian strikes on or near two Ukrainian nuclear plants could be considered “contemporary use of nuclear weapons or nuclear blackmail.”

Kyiv accuses Moscow of repeatedly shelling the Russian-occupied Zaporizhzhia nuclear power plant during the war in Ukraine, and more recently conducting a missile strike near the Pivdennoukrainska nuclear plant.

Moscow denies shelling the Zaporizhzhia plant, accusing Kyiv of being responsible. It did not comment on the Pivdennoukrainska strike.