In an interview with CNN, Biden said Putin is a “rational actor who has miscalculated significantly”. The statement comes at a time when Ukraine has requested a push for Western military aid to defend against missile strikes on its cities by the Russian army.
When asked how realistic he believed it would be for Putin to use a tactical nuclear weapon, Biden responded: “Well, I don’t think he will.”
The threat of a nuclear weapon could lead, Mr Biden said, “to just a horrible outcome.”
He continued: “And not because anybody intends to turn it into a world war or anything, but … the mistakes that can be made, the miscalculations, who knows what would happen?”
In recent weeks, Putin has hinted at the use of nuclear weapons against Ukraine as the military situation has deteriorated for Russian forces.
Mr Biden said during a fundraiser: “We have not faced the prospect of Armageddon since Kennedy and the Cuban Missile Crisis.”
The president also said “there will be consequences” for Saudi Arabia following their alignment with Russia in slashing global oil production.
Russia’s biggest air strikes against Ukraine since the start of the war killed at least 19 people Monday, drove thousands of Ukrainians back into air raid shelters and knocked out electricity in hundreds of towns and villages.
After Monday’s barrage of Russian missiles, Zelensky appealed to the leaders of the Group of Seven nations on Tuesday for more air defence capabilities. The G7 vowed to support Kyiv for “as long as it takes.”
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Ukraine armed forces said: “Over the past 24 hours, the occupiers have again resorted to mass missile strikes – more than 30 cruise missiles, seven air strikes and 25 instances of shelling.”
In the pre-taped interview with Tapper at the White House, the president declined to draw a “red line” for actions against Ukraine that would elicit a direct military response to Russia.
Mr Biden said: “It would be irresponsible of me to talk about what we would or wouldn’t do.”