US President Joe Biden says the United States is imposing a "first tranche" of sanctions on Russia in response to its military escalation against Ukraine.
Biden said the sanctions target two large Russian financial institutions and Moscow's access to international financing as well as Russian oligarchs.
He said the US is "prepared to go further with sanctions" should Russia expand its aggression against its neighbour.
Russian President Vladimir Putin dramatically escalated tensions on Monday by recognising the independence of Ukraine's pro-Russia breakaway regions of Donetsk and Luhansk.
He then ordered troops to enter, claiming they would carry out peacekeeping duties.
"This is the beginning of a Russian invasion of Ukraine," Biden said in justifying the move.
"We still believe that Russia is poised to go much further in launching a massive military attack against Ukraine."
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