Ukraine crisis: What is President Putin's strategy?
4 March 2014 Last updated at 23:38 GMT
The US has accused Russia of an "act of aggression" in Crimea after a dramatic armed confrontation by troops at Belbek airbase.
But Russian President Putin is insisting that Ukraine's elected president was unlawfully removed.
The BBC's Bridget Kendall has this analysis of President Putin's strategy.