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Ukraine conflict: Russian 'outrage' at Sloviansk attack

21 April 2014 Last updated at 17:19 BST

US Vice President Joe Biden has arrived in Ukraine, as a war of words is growing between Moscow and Kiev.

Russian Foreign Minister Sergei Lavrov has accused the Ukrainian authorities of breaking a deal reached last week and failing to rein in the ultra-nationalist group the Right Sector.

Russia has accused the group of carrying out a shooting in Sloviansk on Sunday.

David Stern reports.