Russian soldiers march in Moscow's Red Square during Friday's Victory Day parade, a show of military might amid tensions in Ukraine following Moscow's annexation of Crimea. Kirill Kudryavtsev/AFP/Getty Images hide caption

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Russia's President Vladimir Putin, right, addressed the media Wednesday along with the head of the Organisation for Security and Cooperation in Europe (OSCE), Swiss President Didier Burkhalter. ALEXEY DRUZHININ/AFP/Getty Images hide caption

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Russian President Vladimir Putin as he answered questions on national TV Thursday in Moscow. Alexey Nikolsky/RIO Novosti/Kremlin pool/EPA/Landov hide caption

itoggle caption Alexey Nikolsky/RIO Novosti/Kremlin pool/EPA/Landov

A Russian armored vehicle on the road between Simferopol and Sevastopol in Crimea earlier this month. Russia annexed the region two weeks ago. Other Russian forces, across the border from Ukraine, may pull back in coming days. Viktor Drachev/AFP/Getty Images hide caption

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President Obama, accompanied by Dutch Prime Minister Mark Rutte, speaks during their joint news conference at the conclusion of the Nuclear Security Summit in The Hague on Tuesday. Pablo Martinez Monsivais/AP hide caption

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Armed men stood atop a chimney near Ukraine's naval headquarters in Sevastopol, Crimea, on Wednesday. They raised Russian flags after taking over much of the facility. Vasily Fedosenko /Reuters /Landov hide caption

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A masked man, believed to be a Russian soldier, holds a Crimean flag as members of a pro-Russian self-defense unit stand in formation Monday in the regional capital of Simferopol. Vasily Fedosenko /Reuters /Landov hide caption

itoggle caption Vasily Fedosenko /Reuters /Landov

Troops under Russian command scream orders to turn back before firing warning shots at the Belbek airbase in Crimea. The troops were reacting to a large group of unarmed Ukrainian troops who approached them. Sean Gallup/Getty Images hide caption

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