A Russian man thought to be a multi-millionaire businessman is among three people arrested on fraud and money laundering charges in London on Saturday.
The 58-year-old man was arrested in his mansion on suspicion of money laundering, conspiracy to defraud the Home Office (interior ministry) and conspiracy to commit perjury.
A 35-year-old man and a 39-year-old man were also arrested as part of the investigation, but the National Crime Agency did not reveal their nationalities.
The other men were also arrested on suspicion of fraud and money laundering, with the youngest of the trio also arrested for obstruction of police for trying to make off from the scene with a bag carrying thousands of pounds in cash.
At least 50 NCA officers raided the Russian man's home, described by the NCA as a "multi-million-pound residence." Digital devices and a "significant quantity of cash" were seized, along with the arrests.
Graeme Biggar, Director General of the NCA, said the Agency's special "Combatting Kleptocracy Cell" was behind the investigation and raids. The new arm of the NCA was established this year, and is tasked with "investigating potential criminal activity by oligarchs, the professional service providers that support and enable them and those linked to the Russian regime."
"We will continue to use all the powers and tactics available to us to disrupt this threat," he added.
Since the conflict in Ukraine began, the Kleptocracy Cell has succeeded in 100 "disruptions" - the name it gives to "remove or reduce a criminal threat" linked to Russian oligarchs in the UK.