According to Spiegel, NATO's Supreme Allied Commander in Europe, US General Tod Walters proposed the action in a secret videoconference with representatives of the alliance's partner countries.
He called on partners to expand NATO's presence in Bulgaria and Romania, similar to Poland and the Baltic states, as part of the Enhanced Forward Presence mission.
Walters said it would be in response to a buildup of Russian troops near Ukraine's borders.
Russian Ambassador to the United States Anatoly Antonov said earlier in an interview with the American magazine Newsweek that the rhetoric of Washington and the Western press about Moscow's "aggressive" plans has no basis.
Read more in the material RT.