The US imposed a ban on new investments in Crimea Friday, and barred trade in goods, technology or services with the Ukrainian region annexed by Russia.
US President Barack Obama noted in his executive order that the move was taken to "address the Russian occupation of the Crimea region of Ukraine" and that he authorised sanctions on individuals and entities operating in Crimea by freezing their assets under US jurisdiction and denying them entry to the US, Xinhua reported.
Obama acted after the European Union (EU) took similar actions a day earlier. He said in a statement that his order "is intended to provide clarity to the US corporations doing business in the region and reaffirm that the US will not accept Russia's occupation and attempted annexation of Crimea."
Russia took over Crimea in March as an overwhelming majority of the residents on the peninsula voted to secede from Ukraine and join Russia, following a crisis sparked by the ouster of Ukraine's pro-Russia President Viktor Yanukovych in February.
Washington and its European allies do not recognise the Russian annexation of Crimea, and have slapped rounds of sanctions on Moscow over the episode and what they call Russia's unending efforts to fund and arm separatists in eastern Ukraine.
In his statement, Obama once again urged Russia to end its "occupation and attempted annexation" of Crimea, stop support to separatists in eastern Ukraine, and implement peace deals signed in September in Minsk, a refrain he echoed Thursday when he signed into law a bill aiming for tougher sanctions on Moscow.
President Obama said, however, that his administration had no intention to impose more penalties against Moscow at the moment.
Obama said he did not order fresh sanctions on Crimea under the new law, noting that Washington would "review and calibrate" the sanctions with its allies and partners.
President Vladimir Putin, on his part, had reiterated Thursday that Russia would not bow to external political pressure and would stay firm to protect its national interests.
Speaking at a year-end press conference, Putin had also offered Russian mediation to settle the Ukraine crisis.
He also said Friday, that Russia's military doctrine would remain defensive although the North Atlantic Treaty Organisation (NATO) was building up its military presence in eastern Europe.
