The treaty on security guarantees of Ukraine should be approved at a referendum, Mykhailo Podoliak, the adviser to the head of the President's Office of Ukraine, said.

"The implementation of the decision of the agreement on security guarantees will proceed according to the following scheme: first, it will be a referendum, at which all citizens of Ukraine will express their position on this agreement, on how it should work. After that, ratification by the parliaments of the guarantor countries and the parliament of Ukraine will take place. This is the key issue. That is, we must get the support of society so that this agreement is really consolidating for us," Podoliak said at a briefing following talks with the Russian delegation in Istanbul on Tuesday.

According to him, in a separate clause of the agreement, it is proposed to fix the position of Ukraine and Russia for 15 years to conduct bilateral negotiations on the status of Crimea and Sevastopol.

"As a separate point, we propose to the Russian side the following: that Ukraine and Russia will not use any military or armed forces during this time, while negotiations are ongoing, to resolve the issue of Crimea," Podoliak said.

He added that the issue regarding the territories of ORDLO will be discussed within the framework of negotiations between the Presidents of Ukraine and the Russian Federation, Volodymyr Zelensky and Vladimir Putin.

"As for the territory of ORDLO, these issues are included in a separate paragraph, which will be discussed as part of the negotiations between the presidents of Ukraine and the Russian Federation. That is, all the controversial issues have more or less been discussed, our proposals have been made," Podoliak said.