LONDON — Squatters have occupied a London mansion thought to belong to one of the Russian oligarchs sanctioned by the British government.

The property in Belgrave Square — one of London’s most exclusive neighborhoods, located just moments from Buckingham Palace — is said to be owned by billionaire energy mogul Oleg Deripaska, who was sanctioned by authorities last week over his ties with Russian President Vladimir Putin.

Protesters took occupation of the luxury property early Monday, draping it with Ukrainian flags and a sign saying “this property has been liberated.”

According to the BBC, the group claimed to “do the job” of authorities, who have come under criticism for their apparent delay in clamping down on members of Putin’s inner circle.

Police in riot gear reportedly entered the property midday Monday after reports that the squatters were on the property. It is not clear how the protesters gained access to the building.

In a statement seen by Sky News, the Metropolitan police said they had completed a search of the property and were “satisfied” no protestors were inside. They added that they “continue to engage” with those on the balcony.

Ownership details of the multimillion-pound, historic property at Five Belgrave Square are murky. However, High Court documents named Deripaska as the beneficial owner over a decade ago, according to Sky.

Public records show the mansion was originally purchased and is currently held by Ravellot Limited, an offshore company incorporated in the British Virgin Islands, the BBC has reported.

At the request of the National Crime Agency, five bank accounts belonging to Graham Bonham-Carter, the named contact for Ravellot Limited, are now subject to asset freezing orders over his alleged links to Deripaska.

“We can confirm that the NCA has secured two Account Freezing Orders in respect of five bank accounts held by Mr Graham Bonham-Carter,” the NCA said in a statement shared with CNBC.

“The orders were obtained on the basis that there are reasonable grounds to suspect that the money in the accounts was derived from the laundering of funds of an individual subject to sanctions in the United States, namely Oleg Deripaska.”

The British government on Thursday put Deripaska, founder of metals and hydropower company EN+ and six other businesses, on a growing list of Putin allies sanctioned by authorities. The sanctions state that his assets will be seized and travel restricted.

The tycoon, whose wealth derives from the privatization of Russian state assets, has been under U.S. sanctions since 2018.

The protesters reportedly called for the seven-bedroom mansion, which houses a Turkish bath and home cinema, to be made available to Ukrainian refugees.

It comes after U.K. Housing Minister Michael Gove on Sunday touted a similar idea, telling the BBC that he was exploring the possibility of housing migrants in properties seized by the government.

“I want to explore an option which would allow us to use the homes and properties of sanctioned individuals for as long as they are sanctioned for humanitarian and other purposes,” he told the BBC.