Ukraine had about 46 nuclear warheads working on solid fuel / Photo from Depositphotos

"The nuclear weapons were tactical, they also went to Russia. There were Backfire carriers, these are legendary aircraft. They also were transferred to Russia. If one counts everything – it's somewhere about US$250 billion," Kravchuk told Ukrainian TV host and journalist Alesia Batsman during the Batsman program.

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Yet, he said, Ukraine did not conduct negotiations with the United States on the compensation for this amount.

"It wasn't discussed directly, but the costs were mentioned. At that time, we didn't know the numbers as we do today. I would read, would talk to people, would ask experts. As the president – with all due respect – cannot know all facts and figures. And this is normal, he can't know everything. It was said it would cost a lot to keep the weapons in Ukrainian territory and the costs might be even greater when the weapons were scrapped," Kravchuk explained.

According to him, Ukraine had about 46 nuclear warheads working on solid fuel, and the rest were those working on liquid fuel.

"Liquid fuel in rockets was worse than the nuclear weapons. Chemists told me that if, God forbid, it had spilled somewhere on land, the soil could not be used for decades, or even longer. I spoke about this: "How would we [do this]? We, Ukraine, cannot do this on our own. Russia only wants to take the nuclear warheads," he said.

On December 4, 1994, the Budapest memorandum was signed between Ukraine, the United States, the Russian Federation, and Great Britain; it guaranteed Ukraine territorial integrity and security in exchange for its nuclear arsenal.