Under the program, migrants who turn themselves over to U.S. authorities and, in most cases, request asylum, are returned to Mexico after being given a court date. To pursue their asylum cases they have to wait in Mexico, crossing only for court dates in what is a months-long process.
The program began in January at Tijuana, across from San Diego, and the U.S. government has been expanding it eastward along the border, seeing it as an effective deterrent to the flood of migrants. U.S. authorities began returning migrants at the Tamaulipas city of Nuevo Laredo, on the border with Laredo, Texas, in early July and a few days later added Matamoros, across from Brownsville.
So far more than 20,000 migrants have been returned all along the border to wait in Mexico, Mexican officials say.
On Thursday, some 70 migrants walked sullenly with their heads down across the international bridge into Matamoros. They carried their documents in transparent plastic bags and expressed concerns about how they would wait out the process in a state known for powerful organized crime gangs.
"Donald Trump is just returning everyone," said Emilio Cáceres, a 25-year-old Honduran farmer who said he planned go home rather than wait. Cáceres said he previously was deported from the U.S. and therefore did not envisage a successful asylum application even though he was given a hearing date.
Over 100 more returned Friday.
Earlier in the week, Luis Raxic of Guatemala was returned to Matamoros with his wife and 1½-year-old daughter. He had similar thoughts of giving up and going home because he did not want to expose his daughter to the danger of waiting here.
"One of the agents told us very clearly that they were going to deport us, but only to Mexico and not to our country to save money," Raxic said. "It's a strategy to make us scared and so we'll go back."
Mexico began busing some of the returned migrants out of Tamaulipas to the city of Monterrey in neighboring Nuevo Leon state last month. Authorities said it was for their safety, but many were dropped off in that unfamiliar city in the middle of the night. It was unclear how they would return to the border for their court dates.
Raxic waited for the bus to Monterrey, saying from there his family would look for a way back to Guatemala.
Sensing the danger or already knowing Tamaulipas' reputation, some migrants quickly disperse upon reaching Matamoros in search of lodging and are not seen in the streets. Others choose to stay near the downtown bridge where police and National Guard are present. Some have yet to cross over to the U.S. to file asylum applications and are waiting to be called from a list of more than 1,000 names. Others have recently been returned and are awaiting court dates.
A dozen tents are pitched in the bridge's shadow. Some people simply curl up on blankets in the sweltering heat. In addition to Central Americans, there are migrants from Cameroon, Cuba and Peru.
Mexico has said it will provide more shelter space and job opportunities for migrants sent back to Mexico. On Thursday, the government opened a new shelter in Ciudad Juarez across from El Paso, Texas, where the U.S. is also returning asylum seekers.
Two Matamoros shelters visited by The Associated Press on Thursday were at less than half their capacity, even though some of the migrants camped near the bridge had heard otherwise.
Daisy Maldonado of Honduras sat on the ground playing with her 2-year-old daughter. She and her husband were afraid to move far from the bridge to look for housing or work.
"Since they've told us there is no space in the shelters, why risk it?" she said.
It wasn't clear who had told her that, but many migrants repeated the same information.
Walter Enamorado, from El Salvador, has been sleeping outside the state immigration office near the bridge with his 7-year-old son.
"We're abandoned here, but they haven't even told us if there's a shelter or how to get there," he said.