(CNN) Seventeen alleged members of a global trafficking ring have been charged with transporting hundreds of women from Thailand to the United States for commercial sex purposes.

An indictment unsealed this week accuses the 12 Thai nationals and five Americans of recruiting the women in a sophisticated scheme that dates back to 2009.

They used fraudulent means to obtain visas for the women's relocation to major cities, including Los Angeles, Chicago, Atlanta, Las Vegas and Minneapolis, Minnesota, the Department of Justice alleges.

'Forced to work long hours'

In Minneapolis, their alleged activities raised red flags.

"Once in the United States, victims were allegedly placed in houses of prostitution, where they were forced to work long hours -- often all day, every day," the Department of Justice said in a statement.

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"The women were not allowed to leave the prostitution houses unless accompanied by a member of the criminal organization."

In Minneapolis, authorities started investigating after they noticed Thai women getting transported to hotels and apartments all over the city, the Star Tribune reported.

Federal authorities got involved, leading to the arrests and charges Wednesday. Suspects came from all over the US, including Georgia, Minnesota, Illinois and California.

"The 17 people charged in this indictment ran a highly sophisticated sex trafficking scheme," said US Attorney Andrew Luger of the District of Minnesota.

"They promised women in Thailand a chance at the American dream, but instead exploited them, coerced them and forced them to live a nightmare. In short, the victims lived like modern day sex slaves."

Charges against the suspects include conspiracy to commit sex trafficking, coercion, forced labor, money laundering and visa fraud.

Promises of a good life

To lure the women out of Thailand, recruiters allegedly promised them a better life in the United States and a loan of between $40,000 and $60,000. Once in the US, they were required to pay off their debt using earnings from prostitution, the statement says.

In some cases, the women owed even more money because the suspects allegedly demanded they get breast implants before leaving Thailand and added the cost to the victims' debt.

Visa fraud

In addition to the trafficking accusations, the document alleges, the suspects also obtained fraudulent visas and travel documents to speed up the victims' relocation.

Authorities detailed an intricate operation that used nicknames to refer to the various players involved in the trade. "House bosses" were the owners of the homes used for prostitution while "flowers" were the women exploited for commercial sex, according to the indictment.

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"House bosses were responsible for day-to-day operations, including advertising the 'flowers' for commercial sex, maintaining the houses of prostitution, scheduling appointments with sex buyers ..." the document alleges.

Other operators included "facilitators," who spearheaded the victims' movements in the US, and "runners," who mostly accompanied the women when they left the prostitution house to ensure they don't try to escape, according to the documents.

Thailand human trafficking

The indictment comes months after Thailand received an upgrade in this year's US State Department report on human trafficking. After two years on the list of worst-rated countries, Thailand's efforts in the fight against human trafficking seemed to be paying off.

Although the July report determined trafficking is still a significant problem in Thailand, it cited major improvements in investigations, prosecutions and convictions.

Thai officials said they're aware of the indictments against the 17 suspects, and are working with the US on the case.

"Thailand has adopted a zero tolerance policy toward human trafficking," the nation's ministry of foreign affairs said in a statement.

"Such cases exemplify the need for concerted efforts between nations in bringing the offenders to justice. Thailand stands ready to cooperate with the US."