The Russian ruble has plunged more than 20 per cent in pre-market trading following sanctions placed on the country’s financial institutions after the attack on Ukraine.

       The United States and European Union have banned some Russian banks from the Swift financial system on Saturday in the latest sanction against Vladimir Putin’s attack.

       Western leadership, which also includes the United Kingdom and Canada, expelled Russia from the high-security network that connects thousands of financial institutions around the world.

       The ruble’s value had already fallen as much as 40 per cent following the Kremlin’s decision to send troops into Ukraine on Thursday, and was quoted at 110 to 120 per dollar by Russian banks on Sunday, according to The Wall Street Journal.

       Russia’s currency had yet to trade officially in Asia early on Monday but was quoted on dealing sites at between 98.00 to 100.00 per dollar.

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       The United States has targeted all 10 of Russia’s largest financial institutions holding nearly 80 per cent of the Russian banking sector’s total assets, a senior US administration official said on Saturday.

       The official also said the United States and its allies will launch a task force to “identify, hunt down and freeze the assets of sanctioned Russian companies and oligarchs, their yachts, their mansions, and any ill-gotten gains that we can find and freeze”.

       Russia’s central bank, which has reserves of around $630bn, this weekend urged people to remain calm and not spark a run on its banks.

       It insisted that despite the sanctions imposed on the country, it “has the necessary resources and tools to maintain financial stability and ensure the operational continuity of the financial sector”.

       Sanctions have been put in place to prevent the Bank of Russia from selling overseas assets to support its banks.