Brussels (Belgium) (AFP) - Belgium said Sunday its special forces had boarded and seized an oil tanker from the “shadow fleet” Russia uses to circumvent Western sanctions over the war in Ukraine, in an overnight operation.

The Belgian government said the vessel was intercepted in the North Sea, with aerial support from French military helicopters.

Defence Minister Theo Francken said the tanker was escorted to the port of Zeebrugge after being intercepted in Belgium’s exclusive economic zone.

Prosecutors identified the ship, which was said to be on its way back to Russia, as the “Ethera”.

A spokeswoman for the Belgian federal prosecutor’s office said the ship captain, a Russian national, was being questioned by investigators.

The tanker flew the flag of Guinea, but an on-board inspection confirmed suspicions that it was sailing under a false flag, the office said, adding that authorities have opened a criminal investigation.

“If a ship sails under a false flag, this means that it does not comply with several international regulations,” the statement added.

French President Emmanuel Macron confirmed on X that his country’s naval forces assisted in the operation, calling it a “major blow” to Russia’s so-called “shadow fleet”.

Russia has used a flotilla of ageing tankers of opaque ownership to get around restrictions on its lucrative crude exports imposed over its 2022 all-out invasion of Ukraine.

The Belgian defence ministry said the seized tanker was on the European Union’s sanctions list. The EU has blacklisted hundreds of vessels in a bid to sap Moscow’s war chest.

“Sanctions only matter if they are enforced. Today, we enforced them,” Foreign Minister Maxime Prevot, who is also Belgium’s deputy prime minister, said on X.

- ‘Bad guys’ -

The operation was carried out alongside Belgium’s G7, Nordic and Baltic partners and in coordination with France, he added.

“Great job Belgium stopping these bad guys,” the US ambassador to the country, Bill White, commented on social media.

France provided air support with two NH90 helicopters, the defence ministry said.

Footage of the operation posted online by Macron showed Belgian forces rappelling down from the aircraft to board the ship.

Belgian Prime Minister Bart De Wever on social media congratulated his country’s armed forces on their “professional and decisive conduct” and thanked France for its “essential support”.

Russia’s embassy in Belgium said it had not been officially notified of the tanker’s detention, nor informed about the nationality of its crew.

“The embassy is currently taking the necessary steps to determine whether there are Russian citizens on board and to ensure their legal rights if confirmed,” it said in a Telegram post.

Sanctions aimed at limiting Moscow’s revenues used to pursue its war have shut out many tankers carrying Russian oil from Western insurance and shipping systems.

Ukrainian President Volodymyr Zelensky welcomed Belgium’s “strong action against Moscow’s floating purse” and thanked France for supporting the operation.

“This particular vessel has long been under US, EU, and UK sanctions, but nonetheless continued to illegally transport Russian oil using a false flag and forged documents,” he wrote on X.

In February, it was revealed that two employees of a Russian private security company were aboard another suspected Russian “shadow fleet” tanker seized by France in September.

The two men were employed by Moran Security Group, a Russian private security company, and were tasked with monitoring the crew and gathering intelligence, a source with knowledge of the matter told AFP.

French forces boarded another suspected Russian tanker, the Grinch, in January.

But the ship was later let go after its owner paid a multi-million-euro fine, something an analyst said highlighted legal difficulties related to such operations.

“Belgium deserves credit. But the harder question is what happens next,” said Max Meizlish, of the Foundation for Defense of Democracies, a hawkish Washington-based think tank.

“European governments keep hitting the same wall: they have the will to board these ships, but not always the legal tools to keep them,” he said.

“Europe needs to close the legal gap that keeps turning interdictions into mere delays for the shadow fleet.”