Crimea, Sevastopol officially join Russia as Putin signs final decree.
Russian Prime Minister Medvedev said that Ukraine owes Russia $11 billion because the treaty under which Russia provides Ukraine with cheap gas in return for the Sevastopol naval base was "subject to denunciation".
In addition, he said that Ukraine owes Russia $3 billion for a recent loan in the form of Russian purchase of Eurobonds, and that around $2 billion is owed to Gazprom, Russia's state-controlled gas concern.