The U.S. Treasury announced Thursday that it has frozen the financial assets of the Japanese Yamaguchi-gumi yakuza syndicate as well as those of another criminal organization called the Brothers' Circle.

Yamaguchi-gumi leader Kenichi Shinoda and his second-in-command also face sanctions, along with other key members of the Brothers' Circle.

Shinoda is the kumicho, or godfather, of the almost 40,000-strong Yamaguchi-gumi, Japan's most powerful yakuza crime family. 

Under Shinoda's seven-year-long command, the Yamaguchi-gumi have grown and expanded tremendously. He completed a six-year prison stint in April for illegal gun possession.

The U.S. Treasury estimates the group generates profits of billions of dollars annually from its involvements in weapons trafficking, prostitution, human trafficking, drug trafficking, fraud and money laundering.

Yakuza groups are not illegal in Japan, thus allowing them considerable freedom to operate openly.  They hide their illegal businesses behind a wide array of legitimate ventures.  

The Brothers' Circle is a multi-national, multi-ethnic crime network of groups based in former Soviet Union nations.  The group's operations span from Europe, to the Middle East, Africa and Latin America.   

The Treasury's move follows an executive order issued by President Barack Obama in July 2011 that called for sanctions against the two organizations.

Today's action casts a spotlight on key members of criminal organizations that have engaged in a wide range of serious crimes across the globe, David Cohen, the Treasury undersecretary for terrorism and financial intelligence, said.

They use our financial system. They use our commercial system to both penetrate the markets, to disrupt the markets and to make use of their illicit proceeds.

Today's designations are just the first under our new our sanctions authority to target transnational criminal organizations and isolate them from the global financial system, he added.

The Treasury declined to comment on the total value of the frozen assets.