President Vladimir Putin signed a decree recognising Crimea as a sovereign state after the Ukrainian region declared itself independent and applied to join Russia following a weekend referendum.
The decree, which took effect immediately, says Moscow recognition of Crimea as independent is based on "the will of the people of Crimea".
Crimea's leaders declared a Soviet-style 97-percent result in favour of seceding from Ukraine in a vote condemned as illegal by Kiev and the West. The Crimean parliament formally proposed that Russia "admit the Republic of Crimea as a new subject with the status of a republic".
Putin's decree recognising Crimea as a 'sovereign country' has triggered the toughest sanctions against Russia since the Cold War.
With over half of the votes counted, over 95% of people in Crimea have voted to become part of Russia, election officials have said.
At some point the West's warnings will have to become deeds, part of the problem is they don't know which Putin they're dealing with.