WASHINGTON — A Mexican regulation has stopped the US from quickly turning away migrant households at one of many busiest sections of the southwestern border, forcing brokers to renew releasing households into the nation, in line with three Biden administration officers.

The Trump administration began turning back migrants coming into the US in March, citing the specter of the coronavirus, and the emergency rule successfully sealed the border from asylum seekers. However due to a regulation Mexico handed in November that prohibits the detention of immigrant kids and households, the nation has stopped accepting such households from South Texas, an space usually prone to unlawful crossings, officers mentioned.

The latest shift has alarmed officers on the Division of Homeland Safety and presents an instantaneous problem to the Biden administration. Homeland safety officers have mentioned the emergency rule was mandatory to stop the coronavirus from spreading in detention services alongside the border, even because it prevented susceptible households from having their asylum claims heard. An growing variety of households have been held in latest weeks in such services within the Rio Grande Valley, in addition to in Del Rio, Texas, officers mentioned.

Stephanie Malin, a spokeswoman for Customs and Border Safety, mentioned due to pandemic precautions and social distancing tips, some services had reached full “protected holding capability.”

“C.B.P. takes very severely the security and well-being of its work drive and people they encounter, and we’re taking much more precautions resulting from Covid-19,” Ms. Malin mentioned. “As they all the time have, the variety of people crossing the border continues to fluctuate, and we proceed to adapt accordingly.” She mentioned the company was working with organizations in the neighborhood when releasing migrants into the general public.

The USA has expelled greater than 390,000 migrants again to Mexico or their house nations since March. The rule lowered the variety of migrants detained on the U.S. facet of the border, nevertheless it additionally sent Central American families scrambling at times after they realized that their kids had been delivered to Mexico, a violation of worldwide agreements. And whereas the coverage was an important piece of the Trump administration’s makes an attempt to shut the border to migrants, the rule additionally had the unintended effect of giving migrants extra possibilities to enter illegally.

Customs and Border Safety recorded greater than 73,000 crossings in December, a rise from the greater than 40,000 in July. Brokers detained greater than 40,000 migrants in December 2019.

The Mexican regulation, which took impact in January, doesn’t apply to the whole border, officers mentioned. American border brokers are nonetheless turning again single adults, and in locations like Arizona, households, as effectively, officers mentioned. It’s unclear how the regulation will have an effect on different components of the border.

A spokesman for the Overseas Ministry in Mexico declined to touch upon whether or not it had stopped accepting migrant households, saying solely that the US continued to have the pandemic emergency rule in place.

However the Biden administration has been unable to return migrant households to Reynosa, Mexico, a change that was first reported by The Washington Post. The shift has elicited concern at Customs and Border Safety of a possible rise of crossings by households to the neighboring Rio Grande Valley. Border crossings in recent times have been fueled principally by Central American households fleeing persecution, violence and poverty.

The Division of Homeland Safety is at the moment constructing a tent facility in Donna, Texas, to deal with migrants, however an administration official mentioned that was unrelated to the regulation in Mexico. Customs and Border Safety mentioned in November it might shut the principle detention facility in McAllen for renovations.

President Biden campaigned on restoring asylum on the southwestern border and signed an executive order this week directing the administration to assessment rolling again President Donald J. Trump’s restrictionist insurance policies.

The brand new administration has not detailed publicly when the pandemic emergency rule could be lifted. After a federal judge in the District of Columbia lifted a block on the rule, which prevented the US from turning away unaccompanied migrant kids, the White Home mentioned it might use its discretion in deciding when to use the coverage.

Mr. Biden said in December that his administration would take a cautious strategy to reversing Trump-era insurance policies to keep away from a surge on the border.

His immigration plan concerned relying extra on packages that observe migrants after they’re launched into the US to make sure they present up for immigration court docket and fewer on detaining them.

Mexico, for its half, drew reward for enacting restrictions on who it detained.

“Mexico is making a decisive step to finish immigration detention for youngsters and we’re inspired by this promising improvement,” mentioned Gillian Triggs, the assistant excessive commissioner for the United Nations Excessive Commissioner for Refugees.

Whereas prime officers within the Trump administration argued its emergency rule was solely an try to stop the unfold of the coronavirus, Mr. Trump’s White Home tried to use the policy to further his goals of curbing unlawful immigration.

Kirk Semple contributed reporting from Mexico Metropolis.