Migrants queue near the border fence, after crossing the Rio Bravo river, to request asylum in El Paso
Migrants queue near the border fence, after crossing the Rio Bravo river, to request asylum in El Paso, Texas, U.S., as seen from Ciudad Juarez, Mexico January 5, 2023. Reuters

The Biden administration could bar tens of thousands of migrants arriving at the U.S.-Mexico border from claiming asylum if they passed through another country en route to the United States without seeking protection, according to a proposed regulation rolling out on Tuesday, five sources told Reuters.

The proposed restrictions would be the most sweeping attempt yet by U.S. President Joe Biden to deter people from crossing the border without authorization. Biden is expected to seek re-election in 2024 and has struggled to cope with record numbers of arriving migrants.

Under the new rules, migrants who fail to use existing legal pathways to the United States or seek protection in transit would automatically be considered ineligible for asylum unless they qualify for certain exceptions, the U.S. Department of Homeland Security (DHS) said in January.

The rule, to be announced later on Tuesday, will be subject to a 30-day public comment period and then reviewed before final publication, three of the sources said.

Biden, a Democrat who took office in 2021, initially pledged to restore asylum access that was curtailed under his Republican predecessor, Donald Trump. But advocates and some fellow Democrats have criticized him for increasingly embracing Trump-style restrictions.

Biden's plan to ban certain asylum seekers mirrors similar efforts under Trump that were blocked by federal courts.

Families and single adults will be subject to the restrictions while unaccompanied minors will be exempt, three sources familiar with the matter said, requesting anonymity to discuss the not-yet-public proposal.

The rule will be time-limited to a period of two years, two of the sources said.

The American Civil Liberties Union (ACLU) vowed to fight the Biden rule in court, comparing it to the Trump restriction, which was dubbed a "transit ban" by activists.

"We successfully sued to block the Trump transit ban and will sue again if the Biden administration goes through with its plan," said Lee Gelernt, the ACLU attorney who argued the Trump-era lawsuit.

The Biden administration began discussing the ban and other Trump-style measures last year as a way to reduce illegal crossings if COVID-era restrictions allowing many migrants to be expelled back to Mexico were ended. The administration is moving ahead with tougher asylum rules as the COVID restrictions, known as Title 42, appear likely to sunset on May 11 when the COVID-19 public health emergency terminates.

"This was not our first preference - nor our second," a source familiar with the planning said, adding that the White House is urging Congress to pass comprehensive immigration reform or provide additional funding for border security.

Mexican authorities did not immediately respond to a request for comment.

A members of the Texas National Guard places razor wire on the banks of the Rio Bravo river, as seen from Ciudad Juarez
A member of the Texas National Guard places razor wire on the banks of the Rio Bravo river, the border between the United States and Mexico, with the purpose of reinforcing border security and inhibiting the crossing of migrants into the United States, as seen from Ciudad Juarez, Mexico February 16, 2023. Reuters
Migrants under the Migrant Protection Protocols (MPP) program in Ciudad Juarez
Migrants under the Migrant Protection Protocols (MPP) program stand at the Lerdo-Stanton International Bridge after being returned from the U.S. to Mexico to continue their asylum application, in this picture taken from Ciudad Juarez, Mexico, June 30, 2022. Reuters