LONDON, Nov 25 - Britain sanctioned 30 ships in Russia’s so-called shadow fleet that have been skirting restrictions to transport billions of dollars of petroleum, the Foreign Office said Monday.

It is the biggest sanctions package targeting the fleet of illegitimate and often decrepit ships that are operating illegally to avoid sanctions, the Foreign Office said, The Associated Press reported. The U.K. has now sanctioned 73 tankers, the most of any nation, in efforts to cripple a major funding source for Moscow’s war against Ukraine.