France detained a Russia-linked oil tanker off the coast of Sicily earlier this week, President Emmanuel Macron said Thursday.
"On Tuesday, the French navy boarded the oil tanker Deliver as it was passing off the coast of Sicily in breach of the law of the sea," Macron wrote on X.
Maritime authorities said the vessel, which was flying the Cameroonian flag and sailing from Primorsk in Russia, was being escorted by the French navy to an anchorage for further checks.
Macron said the Deliver was linked to Moscow's so-called "shadow fleet," which is used to circumvent Western sanctions imposed after Russia's invasion of Ukraine in 2022.
The vessels frequently change the flags they fly, a practice known as "flag-hopping," or use invalid registrations in an attempt to avoid tracking.
"We will not allow the 'shadow fleet' to circumvent sanctions and finance Russia's war effort," Macron said.
Since September, France has boarded four other ships believed to belong to Russia's shadow fleet, including one in late May in the Atlantic with the help of Britain and other partners.
Several Western countries have imposed sanctions on hundreds of vessels in Russia's shadow fleet over Moscow's 2022 invasion of Ukraine.
Nearly 600 vessels suspected of being part of Russia's shadow fleet are subject to European Union sanctions.