Dutch Brigadier-General Nico Tak said there has been a significant escalation in both the level and sophistication of Russia's military interference in Ukraine. "We have also detected large quantities of advanced weapons, including air defense systems, artillery, tanks, and armored personnel carriers being transferred to separatist forces in eastern Ukraine," said Tak. Baird called the recent events a "significant provocation" in advanc e of next week's NATO summit in Wales, where the alliance's leaders are expected to hold a special meeting with new Ukrainian President Petro Poroshenko.Ukraine is not a member of NATO, so the alliance is not automatically obliged to come to its defense. President Barack Obama ruled out the possibility that the US will take military action over Ukraine and declined to characterize the assault as an invasion.