Vladimir Putin's daughters have been sanctioned by the US, with the EU expected to follow suit.
Reports of widespread atrocities committed by Russian troops have emerged in recent days, with world leaders including US president Joe Biden calling for investigations into possible war crimes in Bucha.
Mass graves have been uncovered in areas reclaimed by Ukrainian forces from Russian control, as well as reports of torture and rape of citizens.
A senior White House administration official told reporters: “We believe that many of Putin’s assets are hidden with family members, and that’s why we’re targeting them."
Biden wrote on Twitter: "I made clear that Russia would pay a severe and immediate price for its atrocities in Bucha. Today, along with our Allies and partners, we’re announcing a new round of devastating sanctions."
The wife and daughter of Putin's foreign minister Sergey Lavrov will also be hit with sanctions.
Russia is already the subject of crushing sanctions, seeing Russian assets and banking frozen across much of the world.
Hundreds of international companies have pulled out of the country, inflation has hit 15.66%, and the rouble has fallen to an all-time low.
Little is known about the offspring of the Russian president, with reports suggesting he opted to keep them out of the limelight so they could grow into "normal" adults.
Russia's state news agency TASS said in 2020 that Putin does not talk about his personal life "as a matter of security and a desire to remain anonymous for his loved ones so they can live a normal life".
The Russian president is known to have two daughters – Katerina Tikhonova and Mariya Vorontsova – with his ex-wife Lyudmila Putina, who he divorced in 2013.
He is reported to have another daughter, 18-year-old Luiza Rozova, who is understood to live in London with her mother.
There are further reports he has four children with gymnast Alina Kabaeva, 38, who is thought to live in Switzerland.
Little is know about the personal life of Katerina Tikhonova, 35, although she is understood to have been born in 1986 when her family was based in Germany while Putin was working as an intelligence officer for the KGB.
She is known for being a competitive acrobatic rock 'n' roll dancer, a niche dance discipline in which she has competed on the world stage.
As well her her dance career, Tikhonova works in science, it has been reported.
According to the Washington Post, Tikhonova is the deputy director for the Institute for Mathematical Research of Complex Systems at Moscow State University, which deals with artificial intelligence.
The elder sister Mariya Vorontsova, 36, is more reclusive than her younger sister, making few public appearances.
Western reports have claimed she showed a great aptitude for the sciences as a child and during her childhood in East Germany showed great promise in the field.
She and her family moved to Moscow when she was a teenager, before she went on to study biology at St Petersburg State University.
From there, she went to medical school in Moscow.
It is understood that Vorontsova now works as a paediatric endocrinologist and is one of the top experts in Russia on dwarfism.
What sanctions are they facing?
Exact details have not yet been announced, but the pair are expected to be subject to strict travel bans across both the EU and US.
Any assets within the countries are also expected to be frozen.
It is not known exactly what assets each of them may have outside of Russia itself.
Russia's largest banks, Sberbank and Alfa Bank, have been subjected to full blocking sanctions by the US for the first time.
The European Commission proposed a ban on coal imports from Russia and a full transaction ban on four key Russian banks as part of its fifth sanctions package.
In London, a Foreign Office source said announcements would also be coming from the UK side.
On Tuesday, foreign secretary Liz Truss said economic actions so far were having a “crippling impact” and “pushing the Russian economy back into the Soviet era”.
She said sanctions had frozen more than $350bn (£266bn) of “Putin’s war chest”, rendering unavailable more than 60% of the regime’s $604bn (£459bn) of foreign currency reserves.
She will join Nato counterparts in Brussels on Wednesday ahead of Thursday’s full meeting of the alliance’s foreign ministers.