In the race to seize assets tied to sanctioned Russian billionaires, U.S. authorities are alleging that a Russian tycoon acted as the "straw owner” of two yachts worth more than $1 billion, including the $700 million Scheherazade, a superyacht linked to Russian President Vladimir Putin.

Court filings in the South Pacific island of Fiji, where the U.S. is trying to seize the $325 million yacht Amadea, reveal what U.S. officials allege is a nest of offshore shell companies that were set up with the help of a yacht broker to conceal the true owners of both vessels — an allegation that lawyers for the listed owner and the broker dispute. A hearing is scheduled for Wednesday in Fiji on the fate of Amadea.

The layers of companies and trusts, stretching from the Marshall Islands to Switzerland, indicate the beneficial owner of both yachts is the former president of state-controlled Rosneft OJSC, Eduard Khudainatov, according to the documents. Khudainatov doesn't appear on any sanctions lists. But the U.S. alleges the "true beneficial owner” of the 348-foot Amadea, which features a helipad, a mosaic-tiled pool and a lobster tank, is Russian gold billionaire Suleiman Kerimov, who was first sanctioned by Washington in 2018.