The United States has confiscated Iranian oil held on a Russian-operated ship near the Greek island of Evia in the Aegean Sea, according to news reports quoting Greek sources.

Following a “judicial intervention by U.S. authorities concerning the ship’s cargo,” the process is currently under way for the oil “to be handed over” at U.S. government expense, an unidentified official quoted on May 26 by the AP news agency said.

The vessel was temporarily seized by Greek authorities on April 15 when it anchored off the port of Karystos on Evia. At the time, it was flying a Russian flag and was carrying a crew of 19 Russians.

The Greek Coast Guard said it was seized due to suspicions it had breached EU sanctions imposed against Russia due to the war in Ukraine.

It was unclear whether the oil was confiscated because it was Iranian oil subject to U.S. sanctions or whether the action was due to the sanctions on the tanker, which recently changed its name from Pegas to Lana and which has been flying the Iranian flag since May 1.

A source at Greece’s Shipping Ministry quoted by Reuters said the U.S. Department of Justice had “informed Greece that the cargo on the vessel is Iranian oil.”

“The cargo has been transferred to another ship that was hired by the U.S.,” the source added without providing further details.

The United States on May 25 imposed sanctions on what it described as a Russian-backed oil-smuggling and money-laundering network for Iran’s Islamic Revolutionary Guards Corps’ Quds Force.