MEXICO CITY — The Mexican government said Tuesday that it “profoundly laments” the decision by the Trump administration to phase out the program that protects hundreds of thousands of young immigrants from deportation.

The fate of the young immigrants in this program, known as “dreamers,” could have a major effect on Mexico: Nearly 80 percent of the roughly 800,000 people approved under the program are from Mexico.

The Mexican Foreign Ministry said in a statement that it has been pushing for the continuation of the Deferred Action for Childhood Arrivals program, or DACA, since the beginning of the Trump administration, “in order to maintain the protection for hundreds of thousands of young people who are the beneficiaries of the program, the majority of them born in Mexico.”

Mexico's ambassador in Washington has sent letters to U.S. lawmakers arguing about the value these young immigrants provide to American society and pledging the network of Mexican consulates will “redouble its efforts” to support the dreamers, the statement said. If deported, “Mexico will receive with open arms the young Dreamers who return to our country,” it said.

The prospect of hundreds of thousands of new deportees to Mexico poses a significant challenge to President Enrique Peña Nieto's administration.

Between January and July, the U.S. government deported about 90,000 Mexicans, a decline of more than 38,000 people compared with the same period in 2016.

The number of people caught trying to illegally cross the border also has plunged this year.

Humberto Roque Villanueva, the deputy secretary for population, migration and religious issues at Mexico's Interior Ministry, attributed the decline partly to “a certain psychosis” generated by the Trump administration that has discouraged Mexicans from crossing the border.

But he also acknowledged that U.S. Immigration and Customs Enforcement has increased arrests of immigrants in the U.S. interior and was putting more people into the immigration court system.

“We don’t know when the actions by ICE will be reflected in the number of deportees,” he said in an interview before the DACA decision was announced.

For its part, the Trump administration has not changed the way it deports Mexicans: They still arrive by land at 11 border crossing points or on weekly flights to Mexico City, Roque said.

Education Secretary Aurelio Nuño said in a recent interview that Mexico has room in its schools to receive deportees.

“We have the capacity. But the challenge will be if they all want to go to three or four universities, then clearly not. But if we are able to achieve a distribution in many universities of the country, then we shouldn't have problems and we can offer a space to all those who eventually may return,” Nuño said.

DACA provides renewable two-year work permits for immigrants brought to the United States as children, allowing them to live without fear of deportation.

Immigration experts predicted a difficult adjustment period if these immigrants who grew up in the United States end up being sent to an unfamiliar, and in some cases more dangerous, country.

“The majority of them don't speak Spanish, or speak it poorly, or speak it but don't write it,” said Miguel Moctezuma Longoria, a researcher on immigration at the Autonomous University of Zacatecas. “They will be deported to Mexico and arrive, many of them without family here, or if they have family, they don't have close relationships with them. It's the same thing that Mexican migrants feel when they go to the United States: solitude.”

Jaime Jiménez Ornelas, a researcher at the Institute of Social Investigations at the National Autonomous University of Mexico, said he worried about deportations of young people who return to dangerous towns and cities in Mexico that are controlled by drug gangs.

“Where are they going to go? To their places of origin? Remember that in many places in this country there are two powers ... [the government] and the drug traffickers,” he said. “These are the realities that these young people are going to have to suffer, it is nothing comparable to the lives they have lived in the United States.”

— Gabriela Martinez contributed to this report.