UK freezes up to £10 billion in assets of Russian oligarch Roman Abramovich's longtime associates

• The UK has sanctioned two longtime business associates of Russian oligarch Roman Abramovich.
• Up to £10 billion ($10.8 billion) in assets of Eugene Tenenbaum and David Davidovich may be frozen.

The UK government announced on Thursday it is freezing up to £10 billion (or $10.8 billion) in assets of two longtime business associates of Russian oligarch Roman Abramovich.

Sanctions placed on Eugene Tenenbaum and David Davidovich will "cut key revenue sources for Putin's war machine," the government said in a statement, calling it the "largest asset freeze action in UK history."

The UK's Foreign and Commonwealth Office declined to elaborate further on any specific assets that will be frozen.

"We are tightening the ratchet on Putin's war machine and targeting the circle of people closest to the Kremlin. We will keep going with sanctions until Putin fails in Ukraine," UK Foreign Secretary Liz Truss said in a statement.

She added: "Nothing and no one is off the table."

Abramovich, who owns London-based Chelsea Football Club, has faced a slew of UK and EU sanctions, but he has so far avoided any from the US.

According to the UK government, Tenenbaum, who is the director of the Chelsea Football Club, took over the Abramovich-linked investment firm Ervington Investments Limited after Russia invaded Ukraine in late February.

Davidovich then took over the firm from Tenenbaum in March. Forbes described Davidovich as Abramovich's "lower-profile right-hand man," who has worked at a handful of Abramovich's ventures.

This story is developing. Please check back for updates.