US President Barack Obama has ordered a ban on the export of goods, technology and services to Crimea, the BBC reports on Saturday.
The executive order also imposes new sanctions on Russian and Ukrainian individuals and companies.
Mr Obama said the move showed the US would never accept Russia's annexation of Crimea in March.
Similar measures agreed by the European Union earlier this week came into effect on Saturday. Canada announced its own sanction on Crimea on Friday.
US president orders additional sanctions against Crimea
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