"On Monday, NATO Commander Gen. Philip Breedlove had a not-so-subtle message for Russia: it will consider stealth and unofficial invasions to be a trigger for war.http://www.thedailybeast.com/articles/2014/09/15/nato-chief-warns-moscow-no-more-stealth-invasions.html
Europe knows these stealth invasions all too well. Russia first sent teams of special operations forces wearing uniforms without insignia in February into Crimea and then later into eastern Ukraine to work with Russian minorities inside the country to begin an insurrection. Ukraine's military has been fighting these "little green men" ever since. But until recently, Russia has not even acknowledged sending anyone into the country."