The US is imposing what it describes as “swift and severe costs” on Russia after President Vladimir Putin announced the annexation of regions of Ukraine following what the West casts as “sham referenda,” including the targeting of a key figure in Russia’s economy. 

Putin signed documents on Friday to formally begin the process of annexing four regions of Ukraine during a ceremony in the Kremlin, a clear violation of international law amid Russia’s invasion of Ukraine that began seven months ago.

In response, the US is announcing sanctions in coordination with G7 allies. 

The US, a Biden administration official said, is “targeting additional Russian government officials and leaders, their family members, Russian and Belarusian military officials, and defense procurement networks, including international suppliers supporting Russia’s military-industrial complex” through announcements from the Departments of Treasury, Commerce and State. 

That includes sanctions from the Treasury on a key player in keeping the Russian economy afloat: Elvira Sakhipzadovna Nabiullina, an economist who has been leading Russia's central bank since 2013.

More background: Putin has spent years building up his defenses, amassing hundreds of billions in foreign currency reserves, bringing much of Russia's industrial base under state control and selling Russia's vast energy resources to the world. US officials grudgingly acknowledge that Nabiullina has done an effective job managing Russia through this initial phase of the sanctions, just as she did in 2014 after Putin's Crimea annexation triggered a much less severe round of sanctions from the West. 

This time, Nabiullina has deftly raised interest rates, imposed capital controls, and sought holes and workarounds to float an economy under siege. 

"A good central banker can do things to buoy the currency," one senior US official said earlier this year. "They have a very good central banker. We knew that then; we know it now."

Among Biden administration officials, Nabiullina is seen as perhaps the most effective of all of Putin's top lieutenants. 

The US is also placing sanctions on relatives of members of Russia’s National Security Council, visa restrictions on Ochur-Suge Mongush for human rights violations, sanctions on 14 international suppliers for Russia’s military supply chains and adding 57 new entities to Commerce’s Entity List for export controls, the officials said.