Ukrainian citizens were forced to participate in an illegal referendum.

This week, following both major setbacks on the war front and partial mobilization of armed forces, Russia is preparing to forcefully annex the Ukrainian territories it has occupied. Analysts suspect that this move is being made so Russia could maintain some degree of justification in fighting to hold these territories, as the territories, at least as far as Russia is concerned, belong to them.

To facilitate the annexation, Ukrainian citizens in the held territories were forced by Russian occupiers to participate in a referendum for joining Russia, the results of which have show an suspiciously large amount of support.

“Unilateral actions aimed to provide a veneer of legitimacy to the attempted acquisition by force by one state of another state’s territory, while claiming to represent the will of the people, cannot be regarded as legal under international law,” said Rosemary DiCarlo, the UN’s under-secretary-general.

Whether legitimate or not, should the annexation go through, it could signal a rising danger for Ukrainian citizens. Russian President Vladimir Putin has repeatedly stated his willingness to use nuclear weapons to defend territories he believes belong to his country.

“As for the risk of Russia using these votes and subsequent annexation of those territories as a pretext for nuclear strikes — we are conscious of this risk, we understand that it is real,” Yuriy Sak, an advisor to Ukraine’s Defense Minister Oleksii Reznikov, told CNBC.

“Even if Russia’s leader is himself crazy enough to contemplate or even consider conducting a nuclear strike on Ukrainian territory, hopefully not all those people who surround him are that crazy. But again, this is not something we can count on so we, as Ukraine, have to be prepared for the worse and the international community has to be prepared not to budge, not to cave to this nuclear blackmail.”