The US government has frozen the assets of a former top Japanese mafia boss, as Washington steps up efforts to clamp down on criminal activities around the world by the Yakuza and related groups.

The Treasury on Wednesday took action against Tadamasa Goto, a former top boss in the powerful Yamaguchi-gumi crime syndicate, making him the 14th person to be targeted since President Barack Obama named the Yakuza as a significant transnational criminal organisation in 2011.

“Tadamasa Goto possesses deep ties to the Yakuza and has been instrumental to its criminal operations around the world,” said John Smith, acting head of the Office of Foreign Assets Control. “Today’s action denies Goto access to the US financial system and demonstrates our resolve to aggressively combat transnational criminal organisations and their supporters.”