Kremlin spokesman Dmitry Peskov told PBS in an interview on Monday that Russia would resort to nuclear weapons only in the case of a “threat to the existence” of his country.

“But any outcome of the operation (in Ukraine), of course is not a reason for usage of a nuclear weapon,” Peskov said.

“We have a security concept that very clearly states that only when there is a threat for existence of the state, in our country, we can use and we will actually use nuclear weapons to eliminate the threat for the existence of our country,” he added.

Peskov also responded to comments made on the weekend by US President Joe Biden, who said Russian President Vladimir Putin "cannot remain in power".

"It's quite alarming, first of all, it's a personal insult," said the spokesman.

Peskov’s remarks about the use of nuclear weapons came several days after he made similar comments in an interview with CNN's Christiane Amanpour.

During that interview, Peskov repeatedly refused to rule out that Russia would consider using nuclear weapons against what Moscow saw as an "existential threat."

Asked under what conditions Putin would use Russia's nuclear capability, Peskov replied, "if it is an existential threat for our country, then it can be."