Asked about the possibility of Crimea's return to Ukraine, Ilya Ponomarev, ex-deputy of the Russian State Duma (2007-2016), said: "The probability is 100%. The only question is when."

However, he remained skeptical as to the likelihood of the peninsula being used as a springboard for the offensive against mainland Ukraine, according to Glavred.

"Rather, the Crimea-based naval contingent can be used to control natural resources located in the Odesa section of the Black Sea shelf. I think that Ukraine should have held the most serious negotiations with the United States and NATO to protect them," the Russian opposition politician said.

He also added that Russia seeks to complicate the situation with the Crimean population, that is to "wash away" the residents who lived on the peninsula before annexation, and complicate the procedure for returning the peninsula to Ukraine.

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"Look at the Baltic states, where similar processes took place within the Soviet Socialist Republic after 1940: see how many problems these countries have today, and all those unfortunate people who believed in their country and moved there after the occupation became hostages of big political games," Ponomarev summed up.

He also said Russia annually loses 2-3% of GDP as a result of the Western sanctions, but most importantly, it loses its future.

"The oil that is currently being extracted continues to be produced, but [the development] of new fields that require new technologies supplied by Western servicing companies will no longer be available. Due to the sanctions and international isolation, the overwhelming number of foreign investors have left the country and halted new investment projects. Almost all high-tech companies that had so rapidly begun to develop under the Medvedev presidency 'ran away'," he said.

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According to Ponomarev, the annual direct costs of the Russian Federation for the maintenance of the annexed Crimea amount to several billion dollars.

"On the one hand, this figure is not too big for the Russian economy. Although, it is more than Ukraine receives annually for the transit of Russian gas. However, the construction of a bridge [from mainland Russia] to Crimea has deprived the city of Novosibirsk of a bridge across the Ob River and the city of Yakutsk of that across the Lena River, and without the latter, the whole region is very much inhibited in its development," the ex-deputy said.