US President Barack Obama has said Russia's actions in Ukraine violate international law.
Mr Obama said although Mr Putin seemed to have a "different set of lawyers" making different interpretations, he is "not fooling anyone".
He added that Russia's legitimate interests in Ukraine did not give it a right to "use force as a means of exerting influence", and insisted the Ukrainian people should be able to decide their own future.
Russian president Vladimir Putin said he would only use force in Ukraine as a "last resort" as he defended Russia's actions in Crimea.
If you wonder what the attitude of world leaders to the crisis in Ukraine is, you are not alone - I don't think they know either.
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