confirming a new report that russia has begun large-scale air defense drills very close to the ukrainian border. this as the united states dispatches a warship and more fighter jets to the region, raising the stakes in an international standoff over the crimean peninsula. national security correspondent jennifer griffin live at the pentagon. jennifer, how seriously is the pentagon taking these reports of russian movements and drills and so forth especially since they missed the tell against signs the first time around? reporter: well, first of all, gregg, they would push back on some of that characterization. u.s. defense officials tell me that according to the latest intelligence russia appears to be poised for a large air defense drill in western russia. it may have already begun. according to russian news reports there will be 280 miles east of the ukrainian border testing the f-300 air defense missiles, 3500 russian troops,