LONDON—The United States has filed a lawsuit to seize a cargo of oil it says came from Iran rather than Iraq, as stated on the bill of lading, and contravenes U.S. terrorism regulations.

The lawsuit filed with the U.S. District of Columbia on Feb. 3 alleges that Iran sought to mask the origin of the oil by transferring it to several vessels before it ended up aboard the Liberian-flagged Achilleas tanker destined for China.

Washington said the scheme involved multiple entities affiliated with Iran’s Islamic Revolutionary Guards Corps and its elite Quds Force, both of which have been declared as foreign terrorist organizations by the United States.

“Participants in the scheme attempted to disguise the origin of the oil using ship-to-ship transfers, falsified documents, and other means, and provided a fraudulent bill of lading to deceive the owners of the Achilleas into loading the oil in question,” the Department of Justice said in a statement.

It said the Achilleas tanker was subject to seizure based on U.S. terrorism forfeiture laws. The move to seize the cargo followed an investigation by the FBI and Department of Homeland Security.

A source at the tanker’s Greek operator Capital Ship Management said the Achilleas was now heading to the United States in full cooperation with U.S. authorities, where the company has a trading license.

The Achilleas’ last reported position was off the coast of South America. The U.S. Gulf port of Galveston, Texas, was its destination with a scheduled arrival on Feb. 15, Refinitiv ship tracking data showed on Feb. 4.

Iran has not commented on the tanker as yet.

Last year, Washington used civil forfeiture procedures to seize gasoline cargoes it said were being sent from Iran to Venezuela aboard four tankers. The shipments were subsequently transferred to other vessels, which sailed to the United States.

The United States has been at loggerheads with Iran for decades. It has imposed economic sanctions on Tehran over its nuclear program and designated a number of Iranian groups as terrorists.

Relations worsened under President Donald Trump. His administration pulled out of the 2015 nuclear deal between Iran and six world powers, slapped more sanctions on Tehran and killed the head of the Quds Force in an airstrike.

U.S. President Joe Biden’s administration is seeking a diplomatic solution to Iran’s nuclear dispute.