The US expanded the list Russian businesses to be subjected to sanctions because Moscow's support for separatists in Eastern Ukraine, the US Treasury Department said.
Almost all the largest banks with state ownership of over 50 percent were affected, including the Bank of Moscow and the Russian Agriculture Bank.
The sanctions limits the dealings US citizens and companies can have with them.
Sanctions have also been imposed on a shipbuilding company based in St. Petersburg. Any assets held in the US have been frozen and American companies have been prohibited from dealing with them.
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