Kellogg pointed out the pattern of Russia's concern about NATO's expansion to the east.

Russia's concern about the expansion of the NATO military bloc to the east is natural. This was stated on May 29 by the US Special Envoy for Ukraine, Keith Kellogg, on ABC News.

"We have repeatedly talked about this, for us the question of Ukraine's accession to NATO is not worth it. And we are not the only country that thinks so. I can name you four such countries from the alliance. And joining NATO requires the consent of all 32 countries," he said.

The diplomat stressed that Russian President Vladimir Putin and American leader Donald Trump have developed a "strong" personal relationship.

Ukraine's membership in NATO is off the agenda. Why is this important?

Earlier, on May 23, Deputy Speaker of the Polish Sejm Krzysztof Bosak pointed out that there were no plans to invite Ukraine to join NATO. He noted that Polish politicians "misinform themselves" when they talk about the possibility of Kiev joining the bloc, because they do not have a sufficient level of knowledge about the debate at the global level.