French Navy forces intercepted and boarded a tanker in the Mediterranean Sea on Friday, a French government statement said, as President Emmanuel Macron said the vessel was linked to Russia’s sanctioned “shadow fleet” shipping oil in violation of international sanctions tied to Moscow’s war on Ukraine.

French maritime authorities for the Mediterranean said the interception took place in the Western Mediterranean and was carried out with allies, including the United Kingdom, which monitored the ship during the operation. The authorities said the “operation aimed to verify the nationality of the vessel,” which was flying the flag of Mozambique.

The tanker was identified as the Deyna, according to the maritime authorities. They said the vessel was coming from the Russian port of Murmansk and that it was suspected of operating under a false flag designation.

In a statement, the French maritime authorities said the documents found onboard “confirmed doubts about the validity of the flag.” They added that the tanker was diverted and escorted by the French navy to an anchorage point for further checks, before the case was referred to a prosecutor in the port of Marseille.

Macron, in a post on X, called the Deyna a “shadow fleet” vessel and said the companies operating such ships “circumvent international sanctions and violate the law of the sea.” He described the vessels as “war profiteers” that “seek to generate profits and finance Russia’s war effort,” and said France “won’t let this happen.”

The French move fits with a wider European effort to crack down on Russia’s shadow fleet. Russia is believed to use a fleet of hundreds of ships to evade sanctions over its war against Ukraine, and France and other countries have said they are stepping up enforcement.

The AP report also noted that France had intercepted another oil tanker in the Mediterranean in January that it linked to the shadow fleet; that vessel was released last month after paying a multimillion-euro penalty. It added that last September, French naval forces boarded another oil tanker off France’s Atlantic coast that Macron also linked to the shadow fleet, and that Russian President Vladimir Putin denounced that interception as an act of piracy.