(CNN) The Department of Homeland Security plans to bus migrants from Tucson, Arizona, to El Paso, Texas, in an expansion of its controversial program to return migrants to Mexico to wait for their US immigration proceedings, according to two officials.
Migrants would be taken more than 300 miles from where they initially crossed the border, and eventually returned to Mexico from El Paso. The Washington Post first reported the expansion to Tuscon.
There is already infrastructure in place in El Paso for managing the returns, according to a DHS official. At the moment, Tucson doesn't have the capacity to carry out what is known as the "Remain in Mexico" or Migrant Protection Protocols program.
Roughly 60,000 migrants have been returned to Mexico since the program's inception last January.
Officials have previously said that returns to Mexico would be expanded border wide. Tucson was one of the last areas without a program to send migrants back to Mexico.
Mexico plays a "huge role" in the program's expansion progress as well, since the US has to coordinate with Mexico on each location where returns will take place, said the official. The biggest issue for returns to Mexico near Tucson is capacity on the US side. That could change as the program continues to grow, according to the official.
Officials estimate one busload a day of migrants will go from Tucson to El Paso. Once in El Paso, migrants will be interviewed and likely returned to Ciudad Juárez, said the official.
A DHS spokesperson, who declined to be named, said the department is "strengthening MPP implementation and operations at two locations."
"We've always had the option to give people who appear there court dates in other cities but now we are actually transporting them from certain areas over to the cities with courts," said the spokesperson in a statement.
Last month, DHS announced it had expanded the program to the Eagle Pass Port of Entry, in Eagle Pass, Texas, which brought the total number of ports of entry with returns to Mexico to six.
Administration officials have credited the program with helping decrease the number of migrants arriving at the US-Mexico border.
"The men and women of CBP, ICE, and USCIS have been clear over the past two days - MPP works and is a game changer in addressing the ongoing border crisis. Great job by all who are helping make this program stronger," said acting Homeland Security Secretary Chad Wolf in a tweet Friday.