Yeliseyev admitted that a recent statement made by Ukrainian President Petro Poroshenko on the need for the referendum had raised the public interest.

"Firstly, I would like to say that the president said nothing new. The head of state reiterated the long-known position that the last word on Ukraine's accession to NATO should belong to the Ukrainian people," Yeliseyev said at a briefing on Friday.

"And this is the context you should perceive the comment given by the President of Ukraine to a German publication about prospects of the referendum on NATO," he said.

Read alsoWSJ: NATO shelves plan to meet with Ukraine about missile-defense system"But of course, we need certain conditions for this referendum. Both the decisions on and timing of the referendum will depend on the fulfillment of these conditions. And the key one is Ukraine's achievement of adequate compliance with NATO criteria," Yeliseyev said.

As UNIAN reported earlier, Poroshenko announced he would initiate a referendum on the country's accession to NATO.

Four years ago, a mere 16% of Ukrainian citizens supported the idea of holding the referendum, while their share rose to 54% as of today, Poroshenko said in an interview with the German-based Berliner Morgenpost daily newspaper.

"As president, I listen to my nation's opinions and will hold a referendum on NATO membership. If Ukrainians vote for, I'll do my best to secure membership of the Alliance," he said.