WASHINGTON – President Barack Obama has told Russian President Vladimir Putin that Sunday’s referendum on Crimea would never be recognized by the United States.

The two leaders spoke after residents in Crimea voted overwhelmingly to secede from Ukraine and join Russia.

The White House says Obama told Putin the Crimean vote violates the Ukrainian constitution and occurred under duress of Russian military intervention. He said the U.S. was prepared to impose additional penalties on Russia.

Obama urged Putin to work with Ukraine as well as Western nations to resolve the crisis diplomatically. Obama also asked Putin to support the deployment of international monitors to help prevent violence in Ukraine as that country prepares for spring elections.

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