Six pregnant Asian-looking women cross the road. Two others cross in the opposite direction. In a nearby store, about 10 compare baby clothing.

Something is happening in the suburbs of Los Angeles.

Nearby, a string of so-called "maternity hotels," where Asian women -- often Chinese and Taiwanese -- come to give birth to babies who will automatically acquire a US passport -- has recently drawn the attention of authorities.

There is nothing illegal about foreign women giving birth in the United States. But federal officials are investigating possible related crimes, while local officials say planning regulations may have been violated.

Since December, there have been 64 complaints, mostly involving the districts of Hacienda Heights and Rowland Heights, Alex Garcia, an LA County planning department official told AFP.

Inspectors entered 16 of these lodgings for pregnant women, and found that five of them were operating as boarding houses for Chinese or Taiwanese women, he said.

A 26-year-old woman, seven months pregnant, who offers the pseudonym Xui Li, has just arrived from Beijing, to give birth on US soil. As other compatriots, she hesitates before discussing the reason for coming with her.

But in the end she opens up -- not giving her real name, of course -- as she browses in the stroller aisle in a store across the road from Pheasant Ridge, where she lives.

"It's my choice for my baby. Maybe later he can have a good education. US has the best universities in the world. In the future, maybe he can come here if he wants," she tells AFP.

As US citizens, her baby will be eligible for college loans and grants. And her parents will be able to apply for a family visa, if they want to settle in the United States.

A couple, who also ask not to be named, say their reasons are different.

"We want to have another child. After the birth of a child, it's not possible," he says, referring to China's one-child policy -- which only counts the number of officially Chinese children.

"If the child is born in a foreign country, the Chinese (officials) are not going to ask for ID," he added.

USA Baby Care, which has a hotel in Anaheim -- near Disneyland, south of Los Angeles -- offers lodging and prenatal care for expectant mothers -- but offers other reasons to convince Asian women to give birth in the US.

"In the case of political instability or unrest, US citizens enjoy the protection of the US government," it says on a Chinese-language website, which has a picture of a baby next to the Statue of Liberty and US Capitol.

"Even if there is an airspace shut-down, they enjoy priority to get on a plane to leave," notes the service, which has prices ranging from $14,000 to $22,000.

But mothers, like the organizations or people who house them, run serious risks with US authorities, depending on exactly how they go about it.

"There is nothing in the law that makes it illegal for pregnant women to enter the United States," Virginia Kice, regional spokeswoman for the US Immigration and Customs Enforcement (ICE) told AFP.

"However if a pregnant woman or anyone else uses fraud or deception to obtain a visa or gain admission to the United States, that would constitute a criminal act," she added.

"Likewise, that would also be true if someone conspires with others who then commit fraud on his or her behalf.

She noted that the "focus on in any visa fraud probe would be on the instigators or organizers, since that is key to disrupting and ultimately dismantling the criminal activity.

"Often the defendants who orchestrate such schemes face violations beyond just visa fraud," including possible conspiracy, money laundering, and making false statements, she added.

As for those who rent lodgings, they are often in purely residential neighborhoods where commercial activity is illegal. Such services could face prosecution for tax evasion, said Garcia.

But inspectors then face the task of proving that they really are renting out rooms -- difficult if they are not allowed in, if they say they can't speak English, or agree among each other to say they are family member or friends.

In those cases no action can be taken, he said.