Ursula von der Leyen, the president of the European Commission, said that “cutting banks off will stop them from conducting most of their financial transactions worldwide and effectively block Russian exports and imports.”

Ms. von der Leyen said that the trans-Atlantic coalition would also try to cripple Russia’s central bank by freezing its transactions and making it “impossible for the central bank to liquidate assets.”

The targeting of Russia’s central bank could, in the end, prove more consequential than the SWIFT [the "cutting banks off" measure in first paragraph] measures. Russia has spent the last several years bolstering its defenses against sanctions, amassing more than $630 billion in foreign currency reserves by diverting its oil and gas revenue. Those reserves can be used to prop up the ruble, whose value has fallen dramatically amid the latest rounds of sanctions.

Biden administration officials said on Saturday that there would be new restrictions by the United States and allies against selling rubles to Russia, undercutting the country’s ability to support its currency in the face of new sanctions on its financial sector. ...

Emily Kilcrease, a senior fellow at the Center for a New American Security [said]:  “Russia has been taking steps since 2014 to sanctions-proof its economy, in part through the stockpiling of foreign exchange reserves. The central bank sanctions will limit their ability to leverage this asset, along with constraining their ability to conduct monetary policy of any sort to manage the economic damage from other sanctions.”