Ukraine war: Russia blames US and vows response for Crimea deaths BBC.comRussia summons the American ambassador over a deadly attack that Moscow says used US-made missiles Yahoo! VoicesRussia summons US ambassador over ‘barbaric’ missile strike Al Jazeera EnglishRussia placing military near civilians in Crimea, to deter attacks: ISW Business InsiderUkraine sends over 30 drones into Russia The Associated Press