Britain has sanctioned the director of the Chelsea soccer club and another associate of Chelsea owner Roman Abramovich for their close association with the Russian tycoon.
Chelsea Football Club director Eugene Tenenbaum and another Abramovich business associate, David Davidovich, were targeted.
The government said it had imposed a freezing order on $10 billion worth of assets linked to the two men, saying it was the largest asset freeze ever imposed by the government.
"We are tightening the ratchet on [Russian President Vladimir] Putin's war machine and targeting the circle of people closest to the Kremlin," British Foreign Secretary Liz Truss said. "We will keep going with sanctions until Putin fails in Ukraine. Nothing and no one is off the table."
Davidovich will also face a travel ban, meaning he will be refused the right to enter or remain in Britain.
Abramovich, a billionaire businessman, was among several wealthy Russians added last month to British and European Union sanctions. He has denied having close ties to Putin.
On February 24, the day Russia invaded Ukraine, Tenenbaum took full control of Ervington Investments Limited, which has served as an investment vehicle for Abramovich for at least eight years.
The company invested in at least eight firms, including Russia's top search engine Yandex and Via, a ride-sharing app.
Tenenbaum last month told Reuters that his company had purchased Ervington Investments in compliance with all laws and regulations. The firm was transferred again last month to Davidovich. Reuters said it was unable to reach Davidovich immediately for comment.
The British government said when it sanctioned Abramovich that he had been a close ally of Putin for decades.