MOSCOW—The Russian government has awarded the contract to build a $3 billion bridge connecting the Crimean peninsular to the Russian mainland to a longtime ally of President Vladimir Putin who is being targeted by U.S. and EU sanctions.

In a decree published on the government’s official website on Friday the government said it had awarded the contract to build the bridge linking the mainland with the Crimean peninsula, annexed by Moscow from Ukraine in March, to the company Stroygazmontazh.

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