"Illegal oil sales from shadow fleet ships are a critical lifeline for Russia’s war in Ukraine, and we’ll continue to cut them off," Kaja Kallas, the EU's top diplomat, said.
EU forces intercepted and boarded a suspected Russian shadow fleet oil tanker in the Mediterranean on Sunday, according to the bloc's top diplomat.
In a post on X, Kaja Kallas said troops from the EU's Operation Irini boarded the MV Sun tanker for "flag verification," following suspicions that the vessel was sailing under a false flag in breach of international maritime law.
"Illegal oil sales from shadow fleet ships are a critical lifeline for Russia’s war in Ukraine, and we’ll continue to cut them off," she wrote, adding that it was the sixth suspected shadow fleet ship boarded by EU operations in recent months.
Kallas - who confirmed that measures targeting Russia's shadow fleet would be on the agenda at a meeting of EU defence ministers in Ireland on Tuesday - also shared images appearing to show the operation in action.
Operation Irini forces carried out a similar mission in early August, boarding the sanctioned MV Toa Payoh vessel to conduct flag verification.
The tanker was intercepted by the Italian navy's Thaon di Revel to the west of the island of Pantelleria as it was making its way from the port of Cotonou in Benin to Istanbul, according to the Italian Defence Ministry.
In June, French President Emmanuel Macron announced that French forces had also intercepted the Russian shadow fleet oil tanker Deliver as it was sailing off the coast of Sicily "in violation of maritime law".
Earlier that month, Ukraine's foreign minister thanked the UK for its "leadership and decisive action" after British forces intercepted a Russian shadow fleet ship in the English Channel.
Westminster said Royal Marine Commandos and law enforcement officers from the National Crime Agency (NCA) boarded the Russian vessel Smyrtos in an operation that lasted six hours.
Russia uses its shadow fleet to evade Western sanctions on its oil industry, which prevent Moscow from chartering or insuring tankers unless it complies with certain restrictions.
Russia's shadow fleet gets around these restrictions by utilising complex ownership structures, flags of convenience and other tactics designed to mask the origin of its cargo.
Operation Irini was launched in March 2020 and was tasked with enforcing an UN arms embargo on Libya due to the Second Libyan Civil War.
Its original mandate was to counter illegal arms trafficking, gather information on oil smuggling, help disrupt human smuggling and train Libyan institutions responsible for law enforcement and search and rescue operations. Its tasks have since been extended to include safeguarding the EU's interests in the Mediterranean.