Trump administration to expand 'Remain in Mexico' policy beyond San Ysidro port The move is likely to increase tension with Mexican government

The Trump administration plans in coming weeks to expand its policy of turning back asylum seekers at the U.S.-Mexico border beyond the San Ysidro border crossing to new unidentified "targeted locations," senior administration officials said Friday.

The move is likely to increase tensions with the Mexican government, which has said it regards the policy as a unilateral decision by the U.S. that could exacerbate the humanitarian crisis at the border.

The policy, sometimes referred to as "Remain in Mexico," was first implemented earlier this year at the San Ysidro border crossing near San Diego and Tijuana in Mexico as a way to deter asylum seekers. Under past practice, people who claim asylum at the border are allowed to wait in the U.S. while their case winds through the immigration courts, a process that could take months or even years.

"We're looking at all the major cities along the border," said a senior official at the Homeland Security Department, who spoke on condition of anonymity.

The American Civil Liberties Union, Southern Poverty Law Center, and Center for Gender and Refugee Studies have already filed a federal lawsuit challenging the policy.

“This misguided policy deprives vulnerable individuals of humanitarian protections that have been on the books for decades and puts their lives in jeopardy," said Melissa Crow, a senior attorney with the Southern Poverty Law Center.

Homeland Security Secretary Kirstjen Nielsen, who announced the policy Dec. 20 at a Capitol Hill hearing, has defended the move as necessary to curb a massive influx of asylum seekers.

The administration has declined to say how many people have been impacted by the new policy so far. Officials say the number of undocumented migrants arriving at the San Ysidro can fluctuate anywhere from approximately 50 to 100 people a day.

The senior DHS official said the administration is treading carefully in expanding the policy "to get this right." While no area along the border is off the table, the administration is considering where it can be successfully implemented.

"We want to focus on the places where we have resources," the official said. "We want to focus on where Mexico has resources."