Russian anti-corruption campaigner Alexei Navalny has built up huge support on social media.
Read moreVladimir Putin
By Anastasia Golubeva & Sergei Goryashko
BBC Russian
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Video caption: Russia Navalny: The moment poisoned Putin critic was detained Alexei Navalny was detained at an airport in Moscow, moments after arriving from Germany.
Senator Dick Durbin: cyber attack "a virtual invasion of the United States"
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Video caption: Senator Dick Durbin on the cyber attack on US government agencies Senator Dick Durbin on the cyber attack on US government agencies and why he won't be spending Christmas with his extended family this year
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Video caption: Does Putin admit any responsibility for 'new Cold War'? Russian President Vladimir Putin was taking questions at his annual end-of year news conference.