The U.S. government is cracking down on the Japanese mafia -- the yakuza -- and has frozen the American assets of a top gang boss.

Tadamasa Goto was a member of Japan's largest gang, the Yamaguchi-gumi. He held several senior roles within the group until 2008, when he was expelled and forced into retirement. Goto eventually relocated to Cambodia, but is suspected to maintain links to front companies set up by the Japanese mob that are engaged in money laundering, according to the U.S. Treasury.

"Goto possesses deep ties to the yakuza and has been instrumental to its criminal operations around the world," said John E. Smith, acting director of the Treasury's Office of Foreign Assets Control. "Today's action denies Goto access to the U.S. financial system and demonstrates our resolve to aggressively combat transnational criminal organizations and their supporters."

The U.S. government has stepped up its crackdown on the yakuza in recent years -- Goto is the 14th individual affiliated with the Japanese mob that Washington has gone after. The yakuza, engaged in drug trafficking, money laundering, and other illegal activity, has established deep ties over the years with criminal organizations in other countries.

The yakuza: Inside Japan's murky criminal underworld

The Japanese government is also starting to clamp down on the yakuza, which became very powerful in the country over the decades by building strong political and business ties.

In August, the largest gang, the Yamaguchi-gumi -- and Goto's former group -- split into two factions, a sign that the old days of yakuza control are coming to an end.

Japanese police have since been on high alert for escalating violence since the rupture. The last major split occurred in 1984, and resulted in years of violent warfare with assassinations, shootings and attempted bombings that terrified the public. Just a few weeks ago, a top mob boss was found bludgeoned to death.

Yakuza members are known for their strict code of conduct, elaborate tattoos, and the practice of cutting off a finger to settle debts or atone for mistakes.