United States prosecutors announced on Thursday they had dismantled three secret “birth tourism” networks that illegally offer Chinese expectant mothers the chance to give birth in California so their children will have US citizenship.

In total, 19 people were charged in the schemes, in which families were poised to pay tens of thousands of dollars, California's prosecutor Nicola Hanna said in a statement.

The three named “birthing houses” were broken up after an investigation in 2015, which authorities have only now publicly acknowledged.

These organisations allowed foreign nationals, most of them Chinese, to come to the US under falsely obtained tourist visas, for which they often lied about the length and purpose of their visit.

Babies born on American soil are automatically entitled to birthright citizenship.

According to prosecutors, the Chinese networks advised their clients on how to deceive American authorities by telling them, for example, to lie during their consular interviews and wear “loose clothing that would conceal their pregnancies” at ports of entry, according to the prosecutors' statement.

“America's way of life is not for sale,” said Joseph Macias, a Homeland Security investigator for Los Angeles. “HSI will aggressively target those who would make a mockery of our laws and values to benefit and enrich themselves,” he said.

Officials cited as an example one Dongyuan Li, a 41-year-old woman living in Irvine, who used some 20 apartments to house pregnant women.

She rented them to more than 500 women at a price of 40,000 to 80,000 dollars each, the indictment stated and added that she received more than three million dollars in wire transfers from China over the course of two years.

The indictment said several of the suspects are at large, most of them in China.