U.S. prosecutors went to federal court in New York on Friday to seek forfeiture of about $75 million in luxury real estate owned by sanctioned Russian oligarch Viktor Vekselberg, saying the assets are proceeds from sanctions violations.

The case arises from the indictment earlier this month of a Vekselberg business associate, who is accused of helping to buy and manage the properties, even as Vekselberg came under sanctions.

Vekselberg, founder of the Renova Group, a Russian conglomerate, was first sanctioned by the U.S. government in 2018 and again last March following Russia’s invasion of Ukraine.

Prosecutors say Vekselberg used a series of shell companies to buy six real estate properties in the United States between 2008 and 2017: two apartments on Park Avenue in New York City, an estate in the seaside community of Southampton, New York, and two apartments and a penthouse apartment on Fisher Island, Florida.

According to prosecutors, Vladimir Voronchenko, a close friend and business associate of Vekselberg and a U.S. permanent resident, retained a lawyer to help buy the properties and later manage their finances.

Voronchenko was indicted earlier this month on charges of sanctions violation and money laundering in connection with maintaining the Vekselberg properties.

Voronchenko fled to Russia last year and remains at large.

In a civil forfeiture complaint, prosecutors said the properties are “proceeds of sanctions violations, and were involved in international money laundering in promotion of sanctions violations” committed by Voronchenko and others.

The forfeiture complaint came on the anniversary of Russia’s invasion of Ukraine.

“With the filing of this complaint, the United States sends a strong message to those who violate sanctions and engage in money laundering that the United States will use every available tool to forfeit criminal proceeds and will use that money to help our allies in Ukraine under the newly enacted law,” U.S. Attorney Damian Williams said in a statement.

Last April, the Justice Department seized a 78-meter (255-foot), $90 million yacht owned by Vekselberg.

Separately, prosecutors in the Eastern District of New York charged Russian national Ilya Balakaev in connection with a scheme to smuggle sensitive devices used in counterintelligence operations from the United States to Russia for the benefit of the Russian intelligence service.