The US Supreme Court has voted to keep in place a controversial Trump-era policy that blocked thousands of people from crossing the US-Mexico border.
Title 42 gives the government power to automatically expel undocumented migrants seeking entry.
The potential lifting of the policy had prompted concerns that the number of migrants at the border would rise.
The Biden administration said it would comply with the ruling but called for reform of immigration policy.
“We are advancing our preparations to manage the border in a secure, orderly, and humane way when Title 42 eventually lifts and will continue expanding legal pathways for immigration,” it said in a statement.
Bill Cassidy, a Republican senator for Louisiana, said removing Title 42 “would have made our border crisis worse, and the White House seemed willing to let that happen”.
“Glad to see the Supreme Court step in to preserve it, but we need a permanent solution,” he said on Twitter.
Miguel Colmenares, a Venezuelan migrant in the Mexican border city of Tijuana, said: “It breaks my heart that we have to keep waiting.”
“I don’t know what I’m going to do, I haven’t got any money and my family’s waiting for me,” the 27-year-old told Reuters news agency.
The Title 42 policy – applied about 2.5 million times since March 2020 – was originally due to expire on 21 December but, two days before the deadline, Chief Supreme Court Justice John Roberts blocked its termination.
The court’s decision was in response to an emergency appeal from some Republican-led states who had asked for the policy to remain in place.
On Tuesday, the Supreme Court voted 5-4 to extend the temporary stay ordered by Justice Roberts while the case moved forward.