Immigrant parents who pay smugglers to bring their undocumented children into the United States could face criminal prosecution or deportation, under new directives issued by the Department of Homeland Security this week.

"Regardless of the desires of family reunification, or conditions in other countries, the smuggling or trafficking of alien children is intolerable," reads the new DHS memorandum addressed to heads of immigration agencies and signed by Secretary John Kelly.

The Trump administration's policy shift is a stark departure from past immigration enforcement practices, which did not generally penalize relatives -- regardless of their immigration status -- who retrieved unaccompanied minors detained by U.S. authorities.

California is one of the two states in the nation that receives the greatest number of unaccompanied child migrants (the other is Texas). The majority of these children are fleeing three Central American countries plagued by violence and poverty -- El Salvador, Honduras and Guatemala.

More than 153,000 minors traveling without a legal guardian were detained at the U.S.-Mexico border and released to parents and other sponsors in the last three years, according to figures from the Office of Refugee Resettlement, the agency entrusted with the care of unaccompanied migrant kids.

Rafael Lopez was one of them. He embarked on the perilous journey out of his native El Salvador when he was 17, bringing only a backpack with some clothes, his birth certificate and a rosary.

"I prayed a lot," said Lopez, now 19, at his home south of San Francisco. "My whole trip I was praying. I was really scared."

Young people trying to reach the U.S. are vulnerable to sexual assault, robbery, kidnapping and other crimes as they travel through Guatemala and Mexico. Lopez's parents knew the risks, but they went ahead and paid smugglers over $8,000 to guide him by bus, foot and finally a boat across the Rio Grande into Texas.

Lopez's mother, Estela, said the decision to bring her son to the U.S. was heart-wrenching. But she said he couldn't stay in El Salvador because the danger there was greater. Members of a notoriously violent gang, the Mara Salvatrucha or MS-13, had knocked on Lopez's door and threatened to kill him unless he joined, she said.

"If he joins the gangs, they kill him, if he doesn't join, it’s the same," she said, in Spanish. "What forces us to put our children’s lives at risk with a trip to the border is we want them to be away from danger. At least here he has a chance to live."

Supporters of the new immigration enforcement policy believe the Obama administration was too lenient in the way it handled the resettlement of unaccompanied minors. That, in turn, encouraged more undocumented parents to use smugglers to bring their children to the U.S., said Jessica Vaughan, director of policy studies at the Center for Immigration Studies, a think tank that favors restricting immigration. She said she welcomed the Trump administration's tougher stance.

"These steps will help put a stop to this surge of illegal arrivals from Central America and to this practice of parents paying criminal organizations for bringing kids illegally," said Vaughan. "We are returning to a common-sense interpretation of our immigration laws."

Meanwhile, attorneys who represent unaccompanied children in U.S. asylum claims believe the new directive penalizing relatives will hurt children who would otherwise qualify for legal protections in this country.

"On a moral level, on a human level, on a practical level, this policy is just so wrong," said Helen Beasley, an attorney with Community Legal Services in East Palo Alto.

Beasley expects undocumented parents will now be hesitant to undergo the background checks necessary for their children to be released to them from immigration custody. And that hesitancy will mean that kids spend more time in detention, she predicted.

"Being in custody is incredibly traumatic for children," said Beasley. "They may be less likely to articulate the trauma that they’ve suffered in their home countries that would qualify them for legal relief."

She added that children could be deported more swiftly if they don't have the help of a parent or guardian to find a lawyer and apply for asylum or other legal protections.

In Rafael Lopez's case, his father stepped forward to get him out of the custody of the Office of Refugee Resettlement. Lopez then applied for asylum with the help of an attorney at Catholic Charities, a nonprofit that has represented dozens of unaccompanied child migrants in the San Francisco Bay Area in the last year.

Lopez said he won his asylum case just last month.

Now that he is safe here, Lopez is making plans for his future. He said he aims to go to college and study business administration and journalism. For the present, he is working full-time at an auto body shop and taking English lessons.

But Lopez worries the new Homeland Security policies will make it tougher for other young people like himself to flee threats and violence in Central America and reunite with their relatives in this country.

"I can’t imagine how it’s going to be now," said Lopez. "It’s going to be horrible for those kids."

The new guidelines also call for restricting the interpretation of an "unaccompanied" child, which could strip special protections for minors after they are released by immigration authorities to a parent or legal guardian in the U.S. Those children would most likely have to defend their request for asylum before an immigration judge, rather than in an interview with an asylum officer trained to work with kids.

Beasley said the minors she represents often need mental health services to open up about their trauma, and the ability to answer questions about their case in a "non-adversarial" asylum office -- rather than an immigration court -- is key for their claim to succeed.