Britain on Thursday announced new sanctions on “seven of Russia’s wealthiest and most influential oligarchs,” freezing their U.K. assets and banning them from the country, as part of Britain’s “efforts to isolate [Russian President Vladimir] Putin and those around him” in response to Russia’s war on Ukraine. Those sanctioned include Roman Abramovich, owner of the Chelsea soccer team, and two close Putin allies: Rosneft CEO Igor Sechin and Oleg Deripaska, an aluminum with ties to Paul Manafort.

“There can be no safe havens for those who have supported Putin’s vicious assault on Ukraine,” Prime Minister Boris Johnson said in a statement. “We will be ruthless in pursuing those who enable the killing of civilians, destruction of hospitals, and illegal occupation of sovereign allies.” The new sanctions “show once again that oligarchs and kleptocrats have no place in our economy or society,” British Foreign Secretary Liz Truss added. “With their close links to Putin they are complicit in his aggression. The blood of the Ukrainian people is on their hands.”

Britain said the seven Russians have a collective net worth of nearly $20 million. Abramovich alone is worth more than $12 billion, the British government said, citing Forbes. The other sanctioned oligarchs are VTB bank chairman Andrey Kostin, Gazprom chief Alexei Miller, pipeline company Transneft president Nikolai Tokarev, and Bank Rossiya chairman Dmitri Lebedev.

The personal sanctions on oligarchs closely associated with Putin and his government “are incredibly important,” Pavel Khodorkovskiy, the son of a Russian oligarch-turned-dissident, told The Washington Post on Wednesday. “Why? Because they are stemming the flow of capital back to Russia that, at this point, can and will be used to finance the slaughter of Ukrainian people.” But “in terms of oligarchs’ personal influence over Putin, I think that’s a misconception,” he added. “There is none. Putin views them as wallets, as a means to an end.”

Abramovich said last week he decided to sell Chelsea FC, one of the top teams in England’s Premier League, but these sanctions put that plan on hold. Culture Secretary Nadine Dorries said the British government will issue a “special license” allowing Chelsea to continue operating and playing soccer “while, crucially, depriving Abramovich of benefiting from his ownership of the club.”

Separately, wealthy Russians are trying to shift some of their wealth from Switzerland and London to Dubai to shield their assets from Western sanctions, Reuters reported Thursday.