Chelsea FC owner Roman Abramovich has been sanctioned by the UK government as part of its response to Russia's invasion of Ukraine.
The list also includes billionaires Igor Sechin and Oleg Deripaska, both seen as allies of Vladimir Putin.
Prime Minister Boris Johnson said "there can be no safe havens" for those who have supported the invasion.
"Today's sanctions are the latest step in the UK's unwavering support for the Ukrainian people.
"We will be ruthless in pursuing those who enable the killing of civilians, destruction of hospitals and illegal occupation of sovereign allies," Mr Johnson said.
The government had come under pressure to sanction Mr Abramovich, who said he had made the "difficult decision" to sell Chelsea FC earlier this month.
The football club is among the assets frozen as part of the sanctions against Mr Abramovich and its sale is now on hold.
The government said it would issue a special licence that allows fixtures to be fulfilled, staff to be paid and existing ticket holders to attend matches.
Season ticket holders can still attend games they have tickets for but the club can not now sell any more tickets for games.
The club's merchandise shop will be closed.
Mr Abramovich, 55, is alleged to have strong ties to Russian President Vladimir Putin, which he has denied.
The government says Mr Abramovich, who has an estimated net worth of £9.4bn, is "one of the few oligarchs from the 1990s to maintain prominence under Putin".
Mr Abramovich has stakes in steel giant Evraz and Norilsk Nickel. He sold a 73% stake in Russian oil firm Sibneft to state-owned gas titan Gazprom for £9.87bn in 2005.
While the sanctions against him throw Chelsea FC's future in doubt, ministers sought to reassure the club it would not be "unnecessarily harmed".
In a tweet, Culture Secretary Nadine Dorries said holding those who have "enabled the Putin regime to account" was the priority.
"I know this brings some uncertainty, but the government will work with the league and clubs to keep football being played while ensuring sanctions hit those intended," she wrote.
The UK and its western allies have been ratcheting up sanctions against individuals and companies linked to President Putin since the invasion of Ukraine was launched on 24 February.
The government said Thursday's sanctions against "seven of Russia's wealthiest and most influential oligarchs" were part of the UK's "efforts to isolate Putin and those around him".
Among those sanctioned was Oleg Deripaska, a leading industrialist who has had links with British politicians.
Once one of the richest men linked to President Putin, Mr Deripaska made billions from his stake in Russia's aluminium industries, including EN+ Group, and has a multi-million pound property portfolio in the UK.
His net worth is now an estimated £2bn, according to the Foreign Office, and he has been subject to US sanctions since 2018.
Unlike other Russian oligarchs, who have remained silent on the war in Ukraine so far, Mr Deripaska has called for "peace as soon as possible" in a tweet.
Igor Sechin is another wealthy businessman who is said to have deep ties to President Putin.
Named Putin's right-hand man by the UK, Mr Sechin worked with the president when he was mayor in St Petersburg in the 1990s.
Igor Sechin is the chief executive of Rosneft, a Russian state oil company, and has been sanctioned by the US and EU.
Others sanctioned included:
Foreign Secretary Liz Truss said the government had targeted the oligarchs to "ramp up the pressure on the Putin regime and choke off funds to his brutal war machine".
She said: "With their close links to Putin they are complicit in his aggression.
"The blood of the Ukrainian people is on their hands. They should hang their heads in shame."