PARIS (AP) — The French Navy, with support from the United Kingdom, has intercepted an oil tanker under international sanctions that was traveling from Russia, the most recent effort by nations that support Ukraine to target Russian oil exports helping to finance President Vladimir Putin’s war.

French President Emmanuel Macron announced the interception in a post Monday on X, saying the Tagor was boarded on Sunday in the Atlantic. The post included a video showing a person rappelling from a helicopter onto a ship. It is the latest in a series of French naval interceptions of tankers suspected of links to Russia.

“It is unacceptable that boats skirt international sanctions, violate the law of the sea and finance the war that Russia has been waging for more than 4 years against Ukraine,” Macron wrote. “These ships, that don’t respect the most elementary rules of maritime navigation, are also a threat to the environment and everyone’s security.”

Oil revenue is a key part of Russia’s economy, allowing Putin to pour money into the war effort against Ukraine without worsening inflation for everyday people and avoiding a currency collapse.

Russia is believed to be using a fleet of hundreds of ships to evade international sanctions imposed over the war. France and other countries have vowed to crack down on the sanction-busting so-called “shadow fleet.”

French maritime authorities said the tanker was intercepted more than 400 nautical miles west of France, in international waters in the Atlantic. It was traveling from the northwestern Russian port of Murmansk, according to the authorities’ statement.

It said the tanker is suspected of operating under a false flag and that the French navy is now escorting it to an anchorage for more checks.

Tankers previously intercepted by France include the Deyna, boarded in the Mediterranean Sea in March. Another tanker, the Grinch, intercepted in the Mediterranean in January, was released in February after paying a multimillion-euro penalty.