The Mexican government unveiled on Tuesday a new program to transport asylum seekers turned back by U.S. border officials back to their home countries in Central America.

Under the controversial policy known colloquially as "Remain in Mexico," the Trump administration has required more than 16,500 migrants to wait in Mexico while their asylum cases are adjudicated in U.S. courts. With its new program, known as the "Temporary Program of Voluntary Returns," the Mexican government is offering to help these migrants — most who have been stranded in Mexico's border cities — go back to their native countries if they choose to do so.

Mexico's National Migration Institute, a government body, announced that a bus carrying nearly 70 migrants left Chihuahua, a city in the country's northwest, on Tuesday morning and headed towards destinations in Guatemala, Honduras and El Salvador, collectively known as the "Northern Triangle." The trip is the first one under the new program, in which Mexican officials are collaborating with international and local groups taking care of migrants subject to the "Remain in Mexico" policy.

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The Mexican government said the first group of Central American migrants assisted by the program had been previously staying in Ciudad Juárez, El Paso's neighboring city and one of three Mexican border cities that have received asylum seekers returned to Mexico by U.S. authorities. Sixty-six of the 69 people onboard the first bus were subject to the U.S. policy, which is being challenged in court. Forty of them are from Honduras, 22 are from Guatemala and seven are from El Salvador.

"[The Mexican government] will continue to provide support to foreigners who are in Mexico on a regular basis, in order to carry out the return to their countries of origin, if they so request," the National Migration Institute said in a press release.

According to the Mexican government, the migrants who choose to participate in this new program are given documents that allow them to reenter Mexico when the date for their court day in the U.S. approaches. The Mexican government made no commitment to assist migrants who choose to reenter Mexico and make another dangerous journey north to reach the U.S.

The program will nevertheless be a tempting option for many of the thousands of migrants returned under the "Remain in Mexico" policy, officially called by the U.S. government the Migrant Protection Protocols (MPP). While they wait weeks and sometimes months for their day in a U.S. court, these Central American migrants struggle to find shelter and employment in Mexico, some face persecution and extortion and most will show up to court without a lawyer.

The initiative by the Mexican government is slated to expand to assist migrants returned by U.S. authorities to Mexicali and Tijuana, which border Calexico and San Diego, the other two locations where the "Remain in Mexico" policy is in place.

Under the agreement reached by the U.S. and Mexico earlier last month to avert President Trump's threats to impose tariffs on Mexican goods, the Trump administration pledged to "immediately" carry out the expansion of "Remain in Mexico" along the entire southern border, while the Mexican government vowed to bolster enforcement at its northern border and the one with Guatemala.

It is unclear if the new busing program by the Mexican government is part of negotiations with the Trump administration.