Washington: The White House has announced a wide new slate of sanctions on Russia that includes first-time individual sanctions on the two adult daughters of President Vladimir Putin in response to the ongoing invasion of Ukraine.

Asked why the US was targeting Putin's daughters, a senior Biden administration official said the US thought they could be in control of some of their father's assets.

"We believe that many of Putin's assets are hidden with family members, and that's why we're targeting them," said the official who spoke on background to preview the new measures.

The Russian president's two adult daughters-- Katerina Tikhonova and Maria Putina-- are with his former wife Lyudmila Shkrebneva. Maria Putina has been reported living under the assumed name Maria Vorontsova. Tikhonova and Vorontsova, in their 30's, are rarely seen in public and almost never mentioned by their father. The Kremlin has only ever identified them by their first names.

The White House said that Vorontsova and Tikhonova were being added to the sanctions list "for being the adult children of Putin, a person whose property and interests in property are blocked".

The announcement described Tikhonova as "a tech executive whose work supports the GoR [the Russian government] and defence industry".

Tikhonova is director of Innopraktika, a USD 1.7 billion project to create a science centre at Moscow State University, as well as deputy director of the Institute for Mathematical Research of Complex Systems at the same institution. She was married to gas company executive Kirill Shamalov, son of the co-owner of Rossiya Bank, between 2013 and 2018.

Her sister, Vorontsova, the announcement went on, "lead state-funded programs that have received billions of dollars from the Kremlin toward genetics research and are personally overseen by Putin".

Vorontsova is also the eldest of the two sanctioned daughters. She spent much of her early life in Dresden, East Germany, prior to the fall of the Berlin Wall, where her father served as a KGB agent.

She reportedly played the violin as a child and went on to study biology at St Petersburg State University and medicine at Moscow State University. She is married to Dutch businessman Jorrit Faassen and the couple reportedly now live in Moscow.

In addition to Putin's daughters, the US will sanction Foreign Minister Sergey Lavrov's wife Maria Lavrova and Ekaterina Lavrova, his adult child.

The United States has also designated 21 members of Russia's National Security Council, including former President Dmitry Medvedev and Prime Minister Mikhail Mishustin, for their role and authority in crafting the Kremlin's brutal policies and resulting abuses, US State Secretary Anthony Blinken said in a statement.

U.S. officials said this latest round of sanctions was in direct response to shocking new evidence of what are likely to be "war crimes" committed by Russian troops in the Ukrainian town of Bucha.

"There's nothing less happening than major war crimes," President Joe Biden said in a speech Wednesday in Washington.

"Responsible nations have to come together to hold these perpetrators accountable," he said. "Together with our allies and our partners, we're gonna keep raising the economic cost and ratchet up the pain for Putin."

US President Joe Biden has signed sign a new executive order prohibiting any new investment in Russia by Americans, which will apply to both U.S. residents and those living abroad.