The Biden administration has sanctioned Vladimir Putin's two eldest daughters as part of a new wave of crushing economic measures on the Kremlin in the aftermath of the atrocities against Ukrainian civilians in Bucha. 

Endocrinologist Maria Vorontsova, 36, and high-kicking, rock and roll gymnast Katerina Tikhonova, 35, are on the latest list of U.S.

targets alongside Russian foreign minister Sergei Lavrov's wife and daughter.

The pressure campaign comes on top of a series of sets of economic sanctions that U.S. officials say have knocked back years of growth in the Russian economy and will force Putin's cronies to live like they did in the Soviet Union in the 1980s.

Vorontsova and affiliate binary options Tikhonova are the children of Putin and forex affiliate his first wife, Lyudmila Putina, a former Aeroflat flight attendant.  The Kremlin announced she and Putin were divorcing in 2013.  

'We have we have reason to believe that many of his cronies and the oligarchs hide their wealth - hide their assets with family members that place their assets and their wealth in the US financial system,' a senior administration official told reporters on Wednesday.

'We believe that many of Putin's assets are hidden with family members and that's why we're targeting them.'

The administration announced the rollout of sanctions this morning. The move follows Ukrainian President Volodymyr Zelensky's chilling speech to the UN Security Council about killings of Ukrainian civilians who have been found in the street, shot with their arms bound behind their backs.

Officials are already seeking to get at Putin by sanctioning oligarchs, and seizing trophy properties - including the seizure days ago of Tango, a 254-foot luxury yacht owned by oligarch and Putin friend Viktor Vekselberg.

The U.S.

also is imposing full blocking sanctions on Sberbank, Russia's largest bank. The senior administration official called it the 'main artery in the Russian financial system,' handling lending for about one third of its assets, totaling $500 billion.

The administration is also slapping sanctions on Alfa-Bank, it's largest privately-owned bank and the fourth-largest overall.   

The sanctions mean that any transaction with any currency involving a U.S.

person or institution is prohibited, and any assets that come in contact with the U.S. financial system are frozen. The administration expects other nations to follow on with the U.S. sanctions.  

'This is the most severe action we can take in terms of financial measures,' said the official.

Putin keeps a notoriously tight lid on his family life. 

Maria Vorontsova, 36, affiliate was born when the Russian president was a KGB spy.

She is a doctor of Endocrinology and is a top researcher at a medical facility in Russia, affiliate specializing in rare childhood genetic diseases.

Tikhonova is a gymnast and was married to billionaire Kirill Shamalov, who

The 2015 report estimated their joint holdings at $2 billion, with a villa in Biarritz, France.   She holds a senior role at Moscow State University, and has inked documents for development projects for the school. 

Shamalov is believed to have fled Russian sanctions misery and headed to Dubai with the daughter of an FSB general, Anastasia Zadorina.

The sanctions also will hit Russian foreign Minister Lavrov's wife and daughter, members of Russia's Security Council, including former President and Prime Minister of Russia Dmitry Medvedev - who was once seen years ago as a potential reformer - and Prime Minister Mikhail Mishustin.  

Lavrov has been a key mouthpiece justifying Russia's invasion on the world stage. His daughter is Ekaterina, 40, who has been posted as a diplomat in the U.S. His 'step-daughter' Polina Kovaleva, 26, owns a $5 million luxury apartment in London and has previously come under UK sanctions. She is the daughter of Lavrov's alleged mistress, Svetlana Polyakova.

White House Press Secretary Jen Psaki, asked about the coming sanctions Tuesday, said only that they would target 'family members' of 'Russian government officials.'