Ukraine President Volodymyr Zelenskyy had a stark warning for the world over the weekend — prepare for Russia to start using nuclear weapons.

Zelenskyy spoke with CNN’s Jake Tapper over the weekend in an interview about the ongoing war between Russia and Ukraine.

The Ukrainian president told CNN that Russian President Vladimir Putin may soon deploy chemical or nuclear weapons to fight Ukraine.

“Not only me — all of the world, all of the countries have to be worried because it can be not real information, but it can be truth,” Zelensky said in the interview.

“Chemical weapons, they should do it, they could do it, for them the life of the people, nothing. That’s why,” Zelenskyy said. “We should think not be afraid, not be afraid but be ready. But that is not a question for Ukraine, not only for Ukraine but for all the world, I think.”

Questions about Russia’s use of nuclear weapons have been raised since Russia invaded Ukraine at the end of February.

Former Russian Foreign Minister Andrei Kozyrev told Fox News Digital that nuclear weapons may be used “in very, very specific situations,” especially if Putin feels threatened by forces outside of Russia.

“If Russia or one of those countries really threatened in their hearts — existentially, that is … if NATO troops come to Moscow, then probably they will resort to nuclear weapons,” he told Fox News Digital.

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Similarly, CIA Director William Burns said last Thursday that the United States should not “take lightly” the chance that Russia would use these weapons, according to The Hill.

He said that Russia’s recent setbacks may encourage Putin to act a little harsher and unleash nuclear weapons.

“Given the potential desperation of President Putin and the Russian leadership, given the setbacks that they’ve faced so far militarily, none of us can take lightly the threat posed by a potential resort to tactical nuclear weapons or low-yield nuclear weapons,” Burns said.