(CNN) Three people were arrested on charges of running "birth tourism" companies that catered to Chinese clients in Southern California Thursday. It is the first time that criminal charges have been filed in a US federal court over the practice, according to Thom Mrozek, spokesman for the US Attorney's Office.

"Birth tourists" travel to foreign countries to give birth, so that their children acquire the citizenship of that country. In the US, the legal principle of jus soli automatically confers citizenship upon babies born on US soil. Other countries, including Switzerland and Japan , do not grant citizenship automatically unless one or more parents are also citizens.

The three people in custody had not given comment at time of publishing. All were charged "conspiracy to commit immigration fraud, international money laundering and identity theft," according to the DOJ statement.

The charges stem from a 2015 raid of dozens of so-called "maternity hotels," often upscale apartments, where mothers-to-be paid between $15,000 to $50,000 to give birth in the US, according to a statement given at the time by US Immigration and Customs Enforcement (ICE).

The DOJ alleges that the birth tourism operations advertised access to "'the most attractive nationality'; 'better air' and less pollution; 'priority for jobs in US government'; superior educational resources, including 'free education from junior high school to public high school'; a more stable political situation; and the potential to 'receive your senior supplement benefits when you are living overseas.'"

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