Britain on Tuesday imposed new sanctions targeting Russia’s so-called “shadow fleet,” blacklisting 20 additional vessels, as well as 10 individuals and entities linked to the country’s energy and shipping sectors.

Security analysts say the aging fleet is used by Moscow to skirt international sanctions that prohibit it from selling oil.

Hundreds of vessels have been sanctioned by the U.K. and European Union since President Vladimir Putin launched Russia’s full-scale invasion of Ukraine in February 2022.

Britain’s latest asset freezes include Orion Star Group and Rosneft Marine (U.K.), both described as significant players in Russia’s energy sector, as well as a deep-sea research unit within the Russian Defense Ministry.

Two U.K. residents, Vladimir Pristoupa and Olech Tkacz, were also sanctioned for allegedly operating a shadowy network of shell companies that funneled more than $120 million worth of high-tech electronics to Russia.