A family walks near the US-Mexico border fence in Playas de Tijuana, Baja California state, Mexico on Sunday amid the COVID-19 pandemic. Photo: AFP

The US Supreme Court on Tuesday denied President Joe Biden's bid to rescind an immigration policy implemented by his predecessor, Donald Trump, that forced thousands of asylum seekers to stay in Mexico awaiting US hearings.

The court, with three liberal justices dissenting, rejected the Biden administration's effort to block a Texas-based judge's ruling requiring the government to revive Trump's "remain in Mexico" policy, formally known as the Migrant Protection Protocols (MPP) program.

The Supreme Court's 6-3 conservative majority includes three justices appointed by Trump. The brief order by the justices means that US District Judge Matthew Kacsmaryk's ruling now goes into effect.

The Department of Homeland Security said in a statement it regretted the Supreme Court's decision and would continue to "vigorously challenge" the district court ruling. 

As the appeals process continues, it said, the agency will comply with the order "in good faith" and has begun discussions with Mexico.

The court's decision referenced its 2020 ruling that thwarted Trump's bid to end a program introduced by former president Barack Obama that protects from deportation hundreds of thousands of immigrants - often called "Dreamers" - who entered the US illegally as children.

Both cases concern whether the government followed the correct legal process in unwinding a previous administration's policy.

Biden, who has sought since taking office in January to reverse many of Trump's hard-line immigration policies, rolled back the MPP program.

Biden's administration turned to the Supreme Court after Kacsmaryk ruled that the Trump policy would have to be reinstated and the New Orleans-based 5th US Circuit Court of Appeals on August 19 denied the government's request for a delay.

The 5th Circuit's decision said the Biden administration must implement the MPP program in "good faith," which leaves the government some discretion in how to move forward.

Democrats and immigration advocates criticized MPP, saying the policy subjected migrants, primarily from Central America, to dangerous conditions in Mexican border cities.

Trump's administration cited a "security and humanitarian crisis" along the US-Mexican border in refusing to allow migrants seeking asylum, because of a fear of persecution in their home countries, to enter the US ahead of hearings before immigration judges.

Reuters