French naval forces intercepted and diverted the Russian-linked oil tanker Grinch on Thursday in the western Mediterranean in the first known case of a crude oil shipment loaded in Russia’s Arctic being seized under Western sanctions.

The interception marks a significant escalation in enforcement of Western sanctions aimed at cutting revenue that sustains Moscow’s war effort. 

The Grinch, built in 2004, registered under a false Comoros flag and on sanctions lists of the United States, European Union, United Kingdom and other Western governments, had loaded its Arctic crude cargo at Murmansk on Dec. 26, according to maritime tracking data. 

It then travelled down the Norwegian coastline and entered the Mediterranean via the Strait of Gibraltar on Wednesday night before being intercepted. 

The Murmansk port area in northwest Russia serves as a central export hub for crude from the nation’s Arctic oil projects. Supplies from fields including the offshore Prirazlomnoye platform in the Pechora Sea, Varandey in the Timan-Pechora region and Novy Port on the Yamal Peninsula are often collected near Murmansk for onward shipment to global markets. 

Those Arctic grades, including lighter blends such as Novy Port crude, have been increasingly targeted by sanctions intended to cut Russia’s oil revenue.

France’s navy, with intelligence support from the United Kingdom and other allies, boarded the 22-year-old, 249-meter crude oil tanker on the high seas in an operation conducted under the United Nations Convention on the Law of the Sea, Macron said in a social media post. 

“We will not tolerate any violation,” Macron wrote, adding that activities by sanctioned vessels help finance Russia’s war of aggression against Ukraine. 

The vessel has been linked to the so-called “shadow fleet” of tankers that Western nations say are used to circumvent sanctions by sailing under false flags, turning off tracking transponders or using opaque ownership structures to continue transporting Russian oil to markets including Asia. 

French maritime authorities are escorting the Grinch to port in Marseille for inspection as a judicial investigation proceeds. 

“This operation was carried out with the support of several of our allies,” Macron said, stressing both the legality of the action and France’s commitment to enforcing sanctions. “The activities of the shadow fleet contribute to financing [Russia’s] war of aggression against Ukraine,” he added. 

The use of older tankers like the Grinch, often operating outside traditional Western maritime oversight, has frustrated efforts by Europe and the United States to choke off income from Russian oil exports since the invasion of Ukraine in 2022. 

In previous cases, Western authorities have detained or challenged vessels suspected of sanctions violations, but experts say this appears to be the first instance where a tanker carrying crude explicitly loaded from the Russian Arctic has been stopped and diverted mid-voyage. 

French officials declined to specify whether the cargo itself would be confiscated or what charges might be brought, but referred the case to prosecutors in Marseille, who handle maritime law matters. 

The operation reflects an intensifying willingness among EU nations to enforce sanctions at sea, even as Russia adapts its shipping tactics and continues to find buyers for Arctic crude, often at discounted prices.

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