Luxury yachts belonging to some of Russia’s richest men have been seized as sanctions ramp up following the deadly invasion of Ukraine.

French customs officials confirmed on Friday (Australian time) they had taken possession of a yacht owned by Igor Sechin, amid fears it was about to flee the country.

The 85-metre Amore Vero, was seized at a shipyard on France’s Mediterranean coast, where it had been undergoing repairs. The superyacht is said to be worth up to $163 million.

“French customs carried out the seizure of the yacht Amore Vero in La Ciotat as part of the implementation of sanctions by the European Union against Russia,” the French finance ministry said in a statement.

Mr Sechin is a former Russian deputy prime minister and is now the boss of Russian state energy company Rosneft.

Rosneft has declined to comment on the French move, saying only that Mr Sechin was unaware that any company linked to him owned the yacht.

AFP has also been told that another superyacht moored in the Mediterranean port of Monaco, the Quantum Blue, owned by Russian billionaire Sergei Galitsky, was also being checked by customs.

German authorities have denied reports that they also seized the $600 million Dilbar, owned by Russian metal tycoon Alisher Usmanov. The 156-metre vessel remains in a Hamburg shipyard, where it was undergoing an extensive refit, pending further information.

The action came as the BBC reported that some oligarchs sanctioned by the European Union were “shocked” to find their debit cards no longer functioned and they instead had to rely on cash stashes.

It came after US President Joe Biden announced extended sanctions against Russian President Vladimir Putin’s inner circle on Friday.

“The goal is to maximise the impact on Putin and Russia,” Mr Biden said, accusing the oligarchs he had targeted of lining “their pockets with Russian people’s money while Ukraine and the people are hiding in the subway from missiles that are being fired indiscriminately”.

Mr Biden announced the new sanctions on eight members of the Russian elite, along with members of their families, as he warned Russia was intensifying its bloody invasion of Ukraine.

The White House said the people on the list – described as “Putin’s cronies and their family members” – will be cut off from the US financial system, their assets in the US will be frozen and their property will be blocked from use.

“We want him [Putin] to feel the squeeze, we want the people around him to feel the squeeze,” White House spokeswoman Jen Psaki said.

Mr Usmanov is on the list, with the US also preparing to seize his private jet.

In his State of the Union address this week, Mr Biden vowed to chase the “ill-begotten gains” of Russian oligarchs, including their private jets, luxury apartments and yachts.

On Wednesday, the US Justice Department announced a task force  designed to enforce sanctions against oligarchs, called “Kleptocapture”.

Deputy Attorney General Lisa Monaco told ABC News that no one was out of the department’s reach.

“The point of going after Putin’s cronies and Russian oligarchs who seek to violate our laws and shield their assets is to say that nobody is beyond the reach of our system of justice, beyond the reach of our work and cooperation with our allies, and that these cronies and oligarchs who seek to support and bolster the Russian regime shouldn’t be able to get away with that while people are dying,” she said.

Britain also extended sanctions against some of Mr Putin’s closest allies on Friday – Mr Usmanov and former deputy prime minister Igor Shuvalov, who now chairs a Russian bank.

Their assets will be frozen and they will be banned from travelling to Britain. British citizens and businesses will also been banned from dealing with the pair.

-with agencies