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The Ukrainian Foreign Ministry voiced outrage Wednesday against Russia's intention to set up border controls at the straits separating Crimea from Ukraine.

"We consider the Russian Federation's intention as another step towards securing the annexation of the Autonomous Republic of Crimea, which remains an integral part of Ukraine," Foreign Ministry spokesman Eugene Perebiynis told reporters.

Kiev regarded Moscow's move to establish a new boundary with Ukraine as "evidence of a gross violation of the international law" and "disrespect for the sovereignty and territorial integrity of Ukraine within its internationally recognized borders," Perebiynis said.

On Monday, Russian Prime Minister Dmitry Medvedev instructed the Federal Agency for State Border Infrastructure to start arranging the state border with Ukraine in the north of Crimea following the peninsula's integration into Russia.

The Ukrainian autonomous republic of Crimea and the city of Sevastopol became Russian regions in mid-March following a referendum recognized by Moscow.

Kiev has rejected the referendum and Crimea's integration with Russia, saying it was unconstitutional.